powerpc/book3s/32: fix number of bats in p/v_block_mapped()

This patch fixes the loop in p_block_mapped() and v_block_mapped()
to scan the entire bat_addrs[] array.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>