linux-phytec-ti

powerpc/mm/ptdump: Wrap seq_printf() to handle NULL pointers

Lovingly borrowed from the arch/arm64 ptdump code.

This doesn't seem to be an issue in practice, but is necessary for my
upcoming commit.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>