powerpc/mm: Split dump_pagelinuxtables flag_array table

To reduce the complexity of flag_array, and allow the removal of
default 0 value of non existing flags, lets have one flag_array
table for each platform family with only the really existing flags.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>