[MIPS] EMMA2RH: remove dead KGDB code

Get rid of the cross-arch KGDB specific code which shouldn't have been
there in the first place...

Signed-off-by: Sergey Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>