driver: Add support for s390

We do not boot with QEMU because it only supports MARCH_Z900, which is
disabled with clang:

https://github.com/groeck/linux-build-test/blob/b8650ca8cdef921992b71db582b9bbdc4efb0ab3/rootfs/s390/run-qemu-s390.sh#L22
https://git.kernel.org/linus/c263a4e990b7296b074e33aa077239a0a28a818e

We do not use llvm-objdump for the time being because of
ClangBuiltLinux/linux#859.

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Author: nathanchance

driver.sh

@@ -139,6 +139,13 @@ setup_variables() {
       export ARCH=powerpc
       export CROSS_COMPILE=powerpc64le-linux-gnu- ;;
 
+    "s390")
+        config=defconfig
+        image_name=bzImage
+        using_qemu=false
+        OBJDUMP=s390x-linux-gnu-objdump
+        export CROSS_COMPILE=s390x-linux-gnu- ;;
+
     "x86_64")
       case ${REPO} in
         android-*)