Add support for the OMAP4 version of the SHAM module
that is present on OMAP4 and AM33xx SoCs.

The modules have several differences including register
offsets, hardware XORing, and how DMA is triggered.
To handle these differences, a platform_data structure
is defined and contains routine pointers, register offsets,
bit shifts within registers, and flags to indicate whether
the hardware supports XORing and provides SHA1 results in
big or little endian.  OMAP2/OMAP3-specific routines are
suffixed with '_omap2' and OMAP4/AM33xx routines are suffixed
with '_omap4'.

Note: The code being integrated is from the TI AM33xx SDK
and was written by Greg Turner <gkmturner@gmail.com> and
Herman Schuurman (current email unknown) while at TI.

CC: Greg Turner <gkmturner@gmail.com>
CC: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>