powerpc/mm: Convert early cpu/mmu feature check to use the new helpers

This switches early feature checks to use the non static key variant of
the function. In later patches we will be switching cpu_has_feature()
and mmu_has_feature() to use static keys and we can use them only after
static key/jump label is initialized. Any check for feature before jump
label init should be done using this new helper.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>