mfd: Add support for multiple s5m devices

There are many samsung mfd devices.
The s5m core driver try to support various samsung s5m series.
It will cover S5M8767A and S5M8763 and S5M8751.
This patch is enable to support various s5m series.

Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>