gpio: gpio-omap: Revert deferred wakeup quirk handling for regressions

Commit ec0daae6

 ("gpio: omap: Add level wakeup handling for omap4
based SoCs") attempted to fix omap4 GPIO wakeup handling as it was
blocking deeper SoC idle states. However this caused a regression for
GPIOs during runtime having over second long latencies for Ethernet
GPIO interrupt as reportedy by Russell King <rmk+kernel@armlinux.org.uk>.

Let's fix this issue by doing a partial revert of the breaking commit.
We still want to keep the quirk handling around as it is also used for
OMAP_GPIO_QUIRK_IDLE_REMOVE_TRIGGER.

The real fix for omap4 GPIO wakeup handling involves fixes for
omap_set_gpio_trigger() and omap_gpio_unmask_irq() and will be posted
separately. And we must keep the wakeup bit enabled during runtime
because of module doing clock autogating with autoidle configured.

Reported-by: Russell King <rmk+kernel@armlinux.org.uk>
Fixes: ec0daae6

 ("gpio: omap: Add level wakeup handling for omap4
based SoCs")
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Ladislav Michl <ladis@linux-mips.org>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>