OMAP2/3: GPIO: generalize prepare for idle

Currently, the GPIO 'prepare' hook is only called when going to
off-mode, while the function is called 'prepare_for_retention.'  This
patch renames the function to 'prepare_for_idle' and calls it for any
powersate != PWRDM_POWER_ON passing in the powerstate.

The hook itself is then responsible for doing various preparation
based on the powerstate.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
diff --git a/arch/arm/mach-omap2/pm24xx.c b/arch/arm/mach-omap2/pm24xx.c
index 374299e..7816c4e 100644
--- a/arch/arm/mach-omap2/pm24xx.c
+++ b/arch/arm/mach-omap2/pm24xx.c
@@ -107,7 +107,7 @@
 	l = omap_ctrl_readl(OMAP2_CONTROL_DEVCONF0) | OMAP24XX_USBSTANDBYCTRL;
 	omap_ctrl_writel(l, OMAP2_CONTROL_DEVCONF0);
 
-	omap2_gpio_prepare_for_retention();
+	omap2_gpio_prepare_for_idle(PWRDM_POWER_RET);
 
 	if (omap2_pm_debug) {
 		omap2_pm_dump(0, 0, 0);
@@ -141,7 +141,7 @@
 		tmp = timespec_to_ns(&ts_idle) * NSEC_PER_USEC;
 		omap2_pm_dump(0, 1, tmp);
 	}
-	omap2_gpio_resume_after_retention();
+	omap2_gpio_resume_after_idle();
 
 	clk_enable(osc_ck);