bf60x: Add double fault, hardware error and NMI SEC handler

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>

arch/blackfin/include/asm/traps.h

@@ -125,5 +125,7 @@
 	level "   for Supervisor use: Supervisor only registers, all MMRs, and Supervisor\n" \
 	level "   only instructions.\n"
 
+extern void double_fault_c(struct pt_regs *fp);
+
 #endif				/* __ASSEMBLY__ */
 #endif				/* _BFIN_TRAPS_H */