crypto: omap-sham - Fix link error without crypto-engine

The driver was converted to use the crypto engine helper
but is missing the corresponding Kconfig statement to ensure
it is available:

arm-linux-gnueabi-ld: drivers/crypto/omap-sham.o: in function `omap_sham_probe':
omap-sham.c:(.text+0x374): undefined reference to `crypto_engine_alloc_init'
arm-linux-gnueabi-ld: omap-sham.c:(.text+0x384): undefined reference to `crypto_engine_start'
arm-linux-gnueabi-ld: omap-sham.c:(.text+0x510): undefined reference to `crypto_engine_exit'
arm-linux-gnueabi-ld: drivers/crypto/omap-sham.o: in function `omap_sham_finish_req':
omap-sham.c:(.text+0x98c): undefined reference to `crypto_finalize_hash_request'
arm-linux-gnueabi-ld: omap-sham.c:(.text+0x9a0): undefined reference to `crypto_transfer_hash_request_to_engine'
arm-linux-gnueabi-ld: drivers/crypto/omap-sham.o: in function `omap_sham_update':
omap-sham.c:(.text+0xf24): undefined reference to `crypto_transfer_hash_request_to_engine'
arm-linux-gnueabi-ld: drivers/crypto/omap-sham.o: in function `omap_sham_final':
omap-sham.c:(.text+0x1020): undefined reference to `crypto_transfer_hash_request_to_engine'

Fixes: 133c3d43

 ("crypto: omap-sham - convert to use crypto engine")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>