ARM: LPC32xx: Add MMC controller support

This patch adds support for the MMC controller of the LPC32xx SoC to the
platform initialization via the pl08x primecell driver. Lacking more complete
DT support, done via DT auxdata.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>