gpio: gpio-omap: Remove conditional pm_runtime handling for GPIO interrupts

Commit b764a586 ("gpio: omap: Remove custom PM calls and use cpu_pm
instead") moved interrupt using GPIO banks to idle with cpu_pm in order
to drop the use of pm_runtime_irq_safe() in a later patch. The GPIO
banks with no interrupts claimed are still being idled based on PM
runtime calls. However this caused a regression for am437x suspend for
rtc+ddr idle mode where the device cannot enter idle state as reported
by Keerthy <j-keerthy@ti.com>.

To fix the issue, we must not fail the pm_runtime callbacks. For GPIO
interrupts, we already have irq_chip_pm_get increment the PM runtime
use count as pointed out by Grygorii Strashko <grygorii.strashko@ti.com>.

So all we need to do is remove the conditional handling in the
runtime_suspend and resume functions and let the CPU PM notifier idle
the GPIO banks.

Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Fixes: b764a586 ("gpio: omap: Remove custom PM calls and use cpu_pm instead")
Reported-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
[tony@atomide.com: updated patch description, dropped runtime count changes]
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>