cris/kgdb: Make symbols used from asm global

arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_breakpoint':
(.text+0x2c3e): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_breakpoint':
(.text+0x2c48): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_breakpoint':
(.text+0x2c50): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_breakpoint':
(.text+0x2c58): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_breakpoint':
(.text+0x2c60): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o:(.text+0x2c68): more undefined references to `reg' follow
arch/cris/arch-v10/kernel/built-in.o: In function `is_static':
kgdb.c:(.text+0x2d46): undefined reference to `internal_stack'
kgdb.c:(.text+0x2d4e): undefined reference to `handle_exception'
kgdb.c:(.text+0x2d54): undefined reference to `reg'
kgdb.c:(.text+0x2d5c): undefined reference to `reg'
kgdb.c:(.text+0x2d64): undefined reference to `reg'
kgdb.c:(.text+0x2d6c): undefined reference to `reg'
kgdb.c:(.text+0x2d74): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o:kgdb.c:(.text+0x2d7c): more undefined references to `reg' follow
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_serial':
(.text+0x2ef6): undefined reference to `internal_stack'
arch/cris/arch-v10/kernel/built-in.o: In function `kgdb_handle_serial':
(.text+0x2efe): undefined reference to `handle_exception'
arch/cris/arch-v10/kernel/built-in.o: In function `goback':
kgdb.c:(.text+0x2f04): undefined reference to `reg'
kgdb.c:(.text+0x2f0c): undefined reference to `reg'
kgdb.c:(.text+0x2f14): undefined reference to `reg'
kgdb.c:(.text+0x2f1c): undefined reference to `reg'
kgdb.c:(.text+0x2f24): undefined reference to `reg'
arch/cris/arch-v10/kernel/built-in.o:kgdb.c:(.text+0x2f2c): more undefined references to `reg' follow

Make reg, internal_stack, and handle_exception global to fix this.
Rename reg to cris_reg as it's a too generic name for a global symbol.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>