runqemu: validate combos

Error out ealier if the combos is invalid, e.g.:
$ runqemu tmp/deploy/images/qemux86/bzImage-qemux86.bin tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic

This will fail at kernel panic, no we check and error out early. We can
add other checkings in the future.

[YOCTO #11286]

(From OE-Core rev: 8c6f253dfb4899324e91dd5d082190909e2bd25d)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/runqemu

@@ -1209,6 +1209,10 @@ class BaseConfig(object):
             self.bitbake_e = ''
             logger.warn("Couldn't run 'bitbake -e' to gather environment information:\n%s" % err.output.decode('utf-8'))
 
+    def validate_combos(self):
+        if (self.fstype in self.vmtypes) and self.kernel:
+            raise RunQemuError("%s doesn't need kernel %s!" % (self.fstype, self.kernel))
+
     @property
     def bindir_native(self):
         result = self.get('STAGING_BINDIR_NATIVE')
@@ -1240,6 +1244,8 @@ def main():
         config.check_args()
         config.read_qemuboot()
         config.check_and_set()
+        # Check whether the combos is valid or not
+        config.validate_combos()
         config.print_config()
         config.setup_network()
         config.setup_rootfs()