We now have an early hash table on hash MMU, so no need to check
Hash var to know if the Hash table is set of not.

Use mmu_has_feature(MMU_FTR_HPTE_TABLE) instead. This will allow
optimisation via jump_label.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f1766631a9e014b6433f1a3c12c726ddfce34220.1603348103.git.christophe.leroy@csgroup.eu