ARM: dts: imx6q-logicpd: Shutdown LCD regulator during suspend

The LCD power sequencer is very finicky.  The backlight cannot
be driven until after the sequencer is done.  Until now, the
regulators were marked with 'regulator-always-on' to make sure
it came up before the backlight.  This patch allows the LCD
regulators to power down and prevent the backlight from being
used again until the sequencer is ready.  This reduces
standby power consumption by ~100mW.

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>