sh64: dummy unwinder BUG wrappers.

sh64 does not yet support GENERIC_BUG, but still wants unwinder support.
Alias UNWINDER_BUG and UNWINDER_BUG_ON to their BUG counterparts until
the conversion to GENERIC_BUG is completed.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/bug.h

@@ -98,6 +98,11 @@ do {							\
 	unlikely(__ret_unwinder_on);				\
 })
 
+#else
+
+#define UNWINDER_BUG	BUG
+#define UNWINDER_BUG_ON	BUG_ON
+
 #endif /* CONFIG_GENERIC_BUG */
 
 #include <asm-generic/bug.h>