crypto: omap-aes - Add Device Tree Support

Add Device Tree suport to the omap-aes crypto
driver.  Currently, only support for OMAP2 and
OMAP3 is being added but support for OMAP4 will
be added in a subsequent patch.

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>