crypto: fips - Move fips_enabled sysctl into fips.c

There is currently a large ifdef FIPS code section in proc.c.
Ostensibly it's there because the fips_enabled sysctl sits under
/proc/sys/crypto.  However, no other crypto sysctls exist.

In fact, the whole ethos of the crypto API is against such user
interfaces so this patch moves all the FIPS sysctl code over to
fips.c.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>