[MIPS] Change names of local variables to silence sparse (part 2)

This patch is an workaround for these sparse warnings:

include2/asm/mmu_context.h:172:2: warning: symbol 'flags' shadows an earlier one
include2/asm/mmu_context.h:133:16: originally declared here
include2/asm/mmu_context.h:232:2: warning: symbol 'flags' shadows an earlier one
include2/asm/mmu_context.h:203:16: originally declared here
include2/asm/mmu_context.h:277:3: warning: symbol 'flags' shadows an earlier one
include2/asm/mmu_context.h:250:16: originally declared here

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>