switch to standard gpio get/set calls (OMAP and mainline)

This patch replaces some legacy OMAP GPIO calls with the "new" (not
really, any more!) calls that work on most platforms.

The calls addressed by this patch are the simple ones to get and set
values ... for code that's in mainline, including the implementations
of those calls.

Except for the declarations and definitions of those calls, all of
these changes were performed by a simple SED script.  Plus, a few
"if() set() else set()" branches were merged by hand.

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