some drivers switch away from OMAP-specific GPIO calls

This updates most of the OMAP drivers which are in mainline to
switch to using the cross-platform GPIO calls instead of the
older OMAP-specific ones.

This is all fairly brainless/obvious stuff.  Probably the
most interesting bit is to observe that the omap-keypad
code seems to now have a portable core that could work with
non-OMAP matrix keypads.  (That would improve with hardware
IRQ debouncing enabled, of course...)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>