crypto: hmac - add fips_skip support

By adding the support for the flag fips_skip, hash / HMAC test vectors
may be marked to be not applicable in FIPS mode. Such vectors are
silently skipped in FIPS mode.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>