serial: 8250: omap: Support wakeup pinctrl state on suspend

UART can be used as a wakeup source for am62 from suspend to ram states.
To enable wakeup from UART am62 requires a wakeup flag being set in the
pinctrl.

If the device is marked as wakeup enabled, select the 'wakeup' pinctrl
state on suspend and restore the default pinctrl state on resume.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Kendall Willis <k-willis@ti.com>
Link: https://lore.kernel.org/r/20250910-uart-daisy-chain-8250-omap-v2-2-e90d44c1a9ac@ti.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>