[MIPS] kgdb: add arch support for the kernel's kgdb core

The new kgdb architecture specific handler registers and unregisters
dynamically for exceptions depending on when you configure a kgdb I/O
driver.

Aside from initializing the exceptions earlier in the boot process,
kgdb should have no impact on a device when it is compiled in so long
as an I/O module is not configured for use.

There have been quite a number of contributors during the existence of
this patch (see arch/mips/kernel/kgdb.c).  Most recently Jason
re-wrote the mips kgdb logic to use the die notification handlers.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 73ff048..706f939 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -71,6 +71,7 @@
 obj-$(CONFIG_MIPS32_N32)	+= binfmt_elfn32.o scall64-n32.o signal_n32.o
 obj-$(CONFIG_MIPS32_O32)	+= binfmt_elfo32.o scall64-o32.o
 
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_PROC_FS)		+= proc.o
 
 obj-$(CONFIG_64BIT)		+= cpu-bugs64.o