The code in the current implementation of safexcel_hmac_alg_setkey
can be reused by safexcel_cipher.  This patch does just that by
renaming the previous safexcel_hmac_setkey to __safexcel_hmac_setkey.
The now-shared safexcel_hmac_alg_setkey becomes safexcel_hmac_setkey
and a new safexcel_hmac_alg_setkey has been added for use by ahash
transforms.

As a result safexcel_aead_setkey's stack frame has been reduced by
about half in size, or about 512 bytes.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>