serial: Enable SYS_NS16550 on incorrectly migrated platforms

serial: Enable SYS_NS16550 on incorrectly migrated platforms

With the migration to DM_SERIAL in commit 191b10ac70d7 ("PowerPC /
Layerscape: Finish migration to DM_SERIAL") a number of platforms were
incorrectly migrated and did not enable SYS_NS16550 despite previously
having enabled the non-DM NS16650 serial driver. Enable these now.

Fixes: 191b10ac70d7 ("PowerPC / Layerscape: Finish migration to DM_SERIAL")
Reported-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>