i.MX27: Adding PCM038 platform support

This patch adds support for the phyCORE-i.MX27 cpu module (aka pcm038).
It is as generic as possible in order to support any kind of baseboard.

Note: This CPU module implementation can't work without a baseboard
support. Baseboard support can be added by the PCM-970 (included in
this patch stack) or any custom variant.

Signed-off-by: Juergen Beisert <j.beisert@pengutronix.de>