crypto: testmgr - handle endianness correctly in alg_test_crc32c()

The crc32c context is in CPU endianness, whereas the final digest is
little endian.  alg_test_crc32c() got this mixed up.  Fix it.

The test passes both before and after, but this patch fixes the
following sparse warning:

    crypto/testmgr.c:1912:24: warning: cast to restricted __le32

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>