powerpc/kernel: Convert mmu_has_feature() to returning bool

The intention is that the result is only used as a boolean, so enforce
that by changing the return type to bool.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Ellerman 2016-07-27 13:39:42 +10:00
commit a81dc9d995