ASoC: p1022ds: fix incorrect referencing of device tree properties

Device tree integer properties are encoded in big-endian format, but some of
the Freescale ASoC drivers were assuming that the host is in big-endian format
as well.  Although this is true, it's better to use endian-safe accessors.

Also add a check for a failed ioremap() call in the SSI driver.

Signed-off-by: Timur Tabi <timur@freescale.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>