gpio/samsung: Complain loudly if we don't know the SoC

If we don't know the SoC type then we won't add any chips which is rather
unfortunate as neither GPIO nor pinmux APIs will work, breaking lots of
different subsystems. Logging at least provides a hint to the user as to
what's gone wrong.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>