hwrng: cctrng - add missing include to linux/fips.h

This fixes build failure when CONFIG_CRYPTO_FIPS is defined.

Fixes: a583ed31

 ("hwrng: cctrng - introduce Arm CryptoCell driver")
Signed-off-by: Hadar Gat <hadar.gat@arm.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>