boards: shields: add support for low power on G1120B0MIPI using RT595

Add support for low power mode on the G1120B0MIPI using the RT595. This
configuration is tested via a testcase in samples/drivers/display, which
should validate that the display can be driven by the RT595 when
CONFIG_PM and CONFIG_PM_DEVICE are set.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>