i.MX31: add a simple gpio driver

This is a minimal driver, so far only managing output. It will
be used by the mxc_spi.c driver.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
3 files changed