ARM: mxs: Add OCOTP driver

Add yet another OCOTP driver for this i.MX family. This time, it's a driver for
the OCOTP variant found in the i.MX23 and i.MX28. This version of OCOTP is too
different from the i.MX6 one that I could not use the mxc_ocotp.c driver without
making it into a big pile of #ifdef . This driver implements the regular fuse
command interface, but due to the IP blocks' limitation, we support only READ
and PROG functions.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>