crypto: sl3516 - remove redundant initializations of pointers in_sg and out_sg

Pointers in_sg and out_sg are being initialized with values that are
never read, they are being re-assigned the same values later on. The
initializations are redundant, remove them in preference to the later
assignments that are closer to when the pointers are being used.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>