crypto: ccp - Fix AES XTS error for request sizes above 4096

The ccp-crypto module for AES XTS support has a bug that can allow requests
greater than 4096 bytes in size to be passed to the CCP hardware. The CCP
hardware does not support request sizes larger than 4096, resulting in
incorrect output. The request should actually be handled by the fallback
mechanism instantiated by the ccp-crypto module.

Add a check to insure the request size is less than or equal to the maximum
supported size and use the fallback mechanism if it is not.

Cc: <stable@vger.kernel.org> # 3.14.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>