Blackfin arch: Print out debug info, as early as possible

Print out debug info, as early as possible - even before the
kernel initializes the interrupt vectors. Now we can print out debug
messages almost anytime during the boot process.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/arch/blackfin/mach-bf537/head.S b/arch/blackfin/mach-bf537/head.S
index 2c4ae46..3014fe8 100644
--- a/arch/blackfin/mach-bf537/head.S
+++ b/arch/blackfin/mach-bf537/head.S
@@ -224,6 +224,12 @@
 	fp = sp;
 	usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+	SP += -12;
+	call _init_early_exception_vectors;
+	SP += 12;
+#endif
+
 	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
 	call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK