crypto: scatterwalk - Remove unused inline function scatterwalk_aligned()

The scatterwalk_aligned() are no longer used since removing blkcipher
and ablkcipher support, all use of it has been removed since
commit d63007eb

 ("crypto: ablkcipher - remove deprecated
and unused ablkcipher support"), so remove it.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>