crypto: x86/aesni - Refactor the common address alignment code

The address alignment code has been duplicated for each mode. Instead
of duplicating the same code, refactor the alignment code and simplify
the alignment helpers.

Suggested-by: Eric Biggers <ebiggers@kernel.org>
Link: https://lore.kernel.org/all/20230526065414.GB875@sol.localdomain/


Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: linux-crypto@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>