[MIPS] Don't force frame pointers for lockdep on MIPS

Stacktrace support on MIPS doesn't use frame pointers.  Since this option
considerably increases the size of the kernel code, force lockdep to not
use it.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>