Blackfin arch: Clean up trace buffer handling, No major functional changes.

Turns on trace earlier, so crashes at kernel start should print out a
trace, making things easier to debug.

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

diff --git a/arch/blackfin/mach-bf548/head.S b/arch/blackfin/mach-bf548/head.S
index 0e1a254..06751ae 100644
--- a/arch/blackfin/mach-bf548/head.S
+++ b/arch/blackfin/mach-bf548/head.S
@@ -29,6 +29,7 @@
 
 #include <linux/linkage.h>
 #include <asm/blackfin.h>
+#include <asm/trace.h>
 #if CONFIG_BFIN_KERNEL_CLOCK
 #include <asm/mach/mem_init.h>
 #endif
@@ -91,6 +92,10 @@
 	M2 = r0;
 	M3 = r0;
 
+	trace_buffer_start(p0,r0);
+	P0 = R1;
+	R0 = R1;
+
 	/* Turn off the icache */
 	p0.l = (IMEM_CONTROL & 0xFFFF);
 	p0.h = (IMEM_CONTROL >> 16);