crypto: sl3516 - fix duplicated inclusion

drivers/crypto/gemini/sl3516-ce-cipher.c: linux/io.h is included more than once.

Generated by: scripts/checkincludes.pl

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>