crypto: xts - consolidate sanity check for keys

crypto: xts - consolidate sanity check for keys

The patch centralizes the XTS key check logic into the service function
xts_check_key which is invoked from the different XTS implementations.
With this, the XTS implementations in ARM, ARM64, PPC and S390 have now
a sanity check for the XTS keys similar to the other arches.

In addition, this service function received a check to ensure that the
key != the tweak key which is mandated by FIPS 140-2 IG A.9. As the
check is not present in the standards defining XTS, it is only enforced
in FIPS mode of the kernel.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit 28856a9e52c7cac712af6c143de04766617535dc)

Orabug: 27809271

Signed-off-by: John Haxby <john.haxby@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>