MIPS: BMIPS: Add cpu-feature-overrides.h

MIPS: BMIPS: Add cpu-feature-overrides.h

BMIPS_GENERIC being multiplatform and intended to support BMIPS3200,
BMIPS3300, BMIPS4350, BMIPS4380 and BMIPS5000-class processors, there is
not much more we can put in there since they do not share the same I and
D cache line sizes at all (doubled for every new generation
essentially), some processors have a S-cache, some don't, some have a
FPU, some don't.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13013/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>