powerpc/32s: Split and inline flush_range()

flush_range() handle both the MMU_FTR_HPTE_TABLE case and
the other case.

The non MMU_FTR_HPTE_TABLE case is trivial as it is only a call
to _tlbie()/_tlbia() which is not worth a dedicated function.

Make flush_range() a hash specific and call it from tlbflush.h based
on mmu_has_feature(MMU_FTR_HPTE_TABLE).

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/132ab19aae52abc8e06ab524ec86d4229b5b9c3d.1603348103.git.christophe.leroy@csgroup.eu