ARC: DWARF2 .debug_frame based stack unwinder

-Originally written by Rajeshwar Ranga
-Derived off of generic unwinder in 2.6.19 and adapted to ARC

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 4026b5a..6e3996c 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -23,6 +23,7 @@
 #include <asm/irq.h>
 #include <asm/arcregs.h>
 #include <asm/prom.h>
+#include <asm/unwind.h>
 
 #define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))
 
@@ -105,6 +106,8 @@
 	conswitchp = &dummy_con;
 #endif
 
+	arc_unwind_init();
+	arc_unwind_setup();
 }
 
 /*