crypto: sha-mb - Fix big integer constant sparse warning

this patch fixes following sparse warning:

sha1_mb_mgr_init_avx2.c:59:31: warning: constant 0xF76543210 is so big it is long

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>