powerpc/ptdump: Properly handle non standard page size

commit b00ff6d8 upstream.

In order to properly display information regardless of the page size,
it is necessary to take into account real page size.

Fixes: cabe8138 ("powerpc: dump as a single line areas mapping a single physical page.")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a53b2a0ffd042a8d85464bf90d55bc5b970e00a1.1589866984.git.christophe.leroy@csgroup.eu


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>