gpio/rc5t583: add gpio driver for RICOH PMIC RC5T583

The PMIC device RC5T583 from RICOH supports 8 gpios.
Adding gpio driver for this device to access the pins
control through gpio library.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
[grant.likely: slight cosmetic changes]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>