MIPS: Fix gigaton of warning building with microMIPS.

With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III
mode through .set mips3 results in *lots* of warnings like

{standard input}: Assembler messages:
{standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension

during a kernel build.  Fixed by using .set arch=r4000 instead.

This breaks support for building the kernel with binutils 2.13 which
was supported for 32 bit kernels only anyway and 2.14 which was a bad
vintage for MIPS anyway.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/bmips_vec.S b/arch/mips/kernel/bmips_vec.S
index a5bf73d..290c23b 100644
--- a/arch/mips/kernel/bmips_vec.S
+++ b/arch/mips/kernel/bmips_vec.S
@@ -122,7 +122,7 @@
 	jr	k0
 
 	RESTORE_ALL
-	.set	mips3
+	.set	arch=r4000
 	eret
 
 /***********************************************************************
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 7365cd6..a9ce340 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -67,7 +67,7 @@
  */
 NESTED(except_vec3_r4000, 0, sp)
 	.set	push
-	.set	mips3
+	.set	arch=r4000
 	.set	noat
 	mfc0	k1, CP0_CAUSE
 	li	k0, 31<<2
@@ -139,7 +139,7 @@
 	nop
 	nop
 #endif
-	.set	mips3
+	.set	arch=r4000
 	wait
 	/* end of rollback region (the region size must be power of two) */
 1:
@@ -577,7 +577,7 @@
 	ori	k1, _THREAD_MASK
 	xori	k1, _THREAD_MASK
 	LONG_L	v1, TI_TP_VALUE(k1)
-	.set	mips3
+	.set	arch=r4000
 	eret
 	.set	mips0
 #endif
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index 9f904ed..837ff27 100644
--- a/arch/mips/kernel/idle.c
+++ b/arch/mips/kernel/idle.c
@@ -64,7 +64,7 @@
 	if (!need_resched())
 		__asm__(
 		"	.set	push		\n"
-		"	.set	mips3		\n"
+		"	.set	arch=r4000	\n"
 		"	wait			\n"
 		"	.set	pop		\n");
 	local_irq_enable();
@@ -82,7 +82,7 @@
 	if (!need_resched())
 		__asm__(
 		"	.set	push					\n"
-		"	.set	mips3					\n"
+		"	.set	arch=r4000				\n"
 		"	.set	noat					\n"
 		"	mfc0	$1, $12					\n"
 		"	sync						\n"
@@ -103,7 +103,7 @@
 	unsigned long c0status = read_c0_status() | 1;	/* irqs on */
 
 	__asm__(
-	"	.set	mips3			\n"
+	"	.set	arch=r4000			\n"
 	"	cache	0x14, 0(%0)		\n"
 	"	cache	0x14, 32(%0)		\n"
 	"	sync				\n"
diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 752b50a..0cfa7a5 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -31,7 +31,7 @@
 	.endm
 
 	.set	noreorder
-	.set	mips3
+	.set	arch=r4000
 
 LEAF(_save_fp_context)
 	cfc1	t1, fcr31
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S
index f938ecd..abacac7 100644
--- a/arch/mips/kernel/r4k_switch.S
+++ b/arch/mips/kernel/r4k_switch.S
@@ -294,7 +294,7 @@
 1:	.set    pop
 #endif /* CONFIG_CPU_MIPS32_R2 */
 #else
-	.set	mips3
+	.set	arch=r4000
 	dmtc1	t1, $f0
 	dmtc1	t1, $f2
 	dmtc1	t1, $f4
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index b79d13f..4a4f9dd 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -110,7 +110,7 @@
 
 	if (cpu_has_llsc && R10000_LLSC_WAR) {
 		__asm__ __volatile__ (
-		"	.set	mips3					\n"
+		"	.set	arch=r4000				\n"
 		"	li	%[err], 0				\n"
 		"1:	ll	%[old], (%[addr])			\n"
 		"	move	%[tmp], %[new]				\n"
@@ -135,7 +135,7 @@
 		: "memory");
 	} else if (cpu_has_llsc) {
 		__asm__ __volatile__ (
-		"	.set	mips3					\n"
+		"	.set	arch=r4000				\n"
 		"	li	%[err], 0				\n"
 		"1:	ll	%[old], (%[addr])			\n"
 		"	move	%[tmp], %[new]				\n"