ARM: imx: don't abort MMDC probe if power saving status doesn't match

The power saving status bit will not signal if the MMDC is under load,
which is likely during kernel boot. There is no point in checking this
bit and aborting the probe, as there is nothing depending on power
saving being enabled, so we can trust the memory controller to enable
power saving when we allow it.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>