crypto: omap-sham - Add code to use dmaengine API

Add code to use the new dmaengine API alongside
the existing DMA code that uses the private
OMAP DMA API.  The API to use is chosen by
defining or undefining 'OMAP_SHAM_DMA_PRIVATE'.

This is a transitional change and the code that uses
the private DMA API will be removed in an upcoming
commit.

CC: Russell King <rmk+kernel@arm.linux.org.uk>
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>