[ARM] cputype: separate definitions, use them

Add asm/cputype.h, moving functions and definitions from asm/system.h
there.  Convert all users of 'processor_id' to the more efficient
read_cpuid_id() function.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/watchdog/ixp4xx_wdt.c b/drivers/watchdog/ixp4xx_wdt.c
index 8302ef0..147b4d5 100644
--- a/drivers/watchdog/ixp4xx_wdt.c
+++ b/drivers/watchdog/ixp4xx_wdt.c
@@ -174,10 +174,8 @@
 static int __init ixp4xx_wdt_init(void)
 {
 	int ret;
-	unsigned long processor_id;
 
-	asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
-	if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
+	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
 		printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
 			" - watchdog disabled\n");