crypto: mxc-scc - add basic driver for the MXC SCC

According to the Freescale GPL driver code, there are two different
Security Controller (SCC) versions: SCC and SCC2.

The SCC is found on older i.MX SoCs, e.g. the i.MX25. This is the
version implemented and tested here.

As there is no publicly available documentation for this IP core,
all information about this unit is gathered from the GPL'ed driver
from Freescale.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>