crypto: omap-sham - Remove usage of private DMA API

Remove usage of the private OMAP DMA API.
The dmaengine API will be used instead.

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>