mmu-hash32: Split BAT size logic from permissions logic

mmu-hash32: Split BAT size logic from permissions logic

hash32_bat_size_prot() and its 601 variant, as the name suggests, returns
both a BAT's size - needed to search for a matching BAT - and its
permissions, only relevant once a matching BAT has been located.

There's no particular advantage to combining these, so we split these roles
into seperate functions for clarity.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>