s390/crypto: add s390 platform specific aes gcm support.

This patch introduces gcm(aes) support into the aes_s390 kernel module.

Signed-off-by: Patrick Steuer <patrick.steuer@de.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>