use standard gpio get/set calls (OMAP tree only)

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 has NOT merged to mainline.

Except for the Documentation file, all of these changes were performed
by a simple SED script.  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>