powerpc/mm/hash: Add helper for finding SLBE LLP encoding

Replace opencoding of the same at multiple places with the helper.
No functional change with this patch.

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