DM: Use the pass-through mode for IPU on 4.19 kernel

Now the IPU mediator driver is not ready on 4.19-rcX kernel. So the IPU will
fallback to pass-trhough mode temporally and be assigned to guest directly.
After the IPU mediator driver is ready, the ipu_passthrough flag will be
changed to zero.

V1-V2: Describe the issue clearly in commit log.

Tracked-on: https://github.com/projectacrn/acrn-hypervisor/issues/1373
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Wu, Binbin <binbin.wu@intel.com>

devicemodel/samples/apl-mrb/launch_uos.sh

@@ -1,7 +1,15 @@
 #!/bin/bash
 
+
+kernel_version=$(uname -r | awk -F. '{ printf("%d.%d", $1,$2) }')
+
 ipu_passthrough=0
 
+# this is the temporal solution before IPU is ready on 4.19
+if [ "$kernel_version" = "4.19" ]; then
+ipu_passthrough=1
+fi
+
 function launch_clearlinux()
 {
 if [ ! -f "/data/$5/$5.img" ]; then