Revert "gpio: omap: Fix lost edge wake-up interrupts"

This reverts commit a522f1d0

.

With cpu_pm handling fixed for omaps, and with gpio-omap now returning
notify error on pending interrupts, we can drop the old workaround for
seeing if there may be pending edge interrupts.

Depends-on: ARM: OMAP2+: Handle errors for cpu_pm
Depends-on: gpio: omap: Block idle on pending gpio interrupts
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: Peter Ujfalusi <peter.ujfalusi@ti.com>
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>
Link: https://lore.kernel.org/r/20200304225433.37336-4-tony@atomide.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>