prepare-emmc-qemu: Check if xzdec is present

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
Change-Id: Iee33c50e23cb5c4c46c7c326b65457aea594d5c7
diff --git a/prepare-emmc-qemu/prepare-emmc-qemu b/prepare-emmc-qemu/prepare-emmc-qemu
index e7cbadf..d0b854a 100755
--- a/prepare-emmc-qemu/prepare-emmc-qemu
+++ b/prepare-emmc-qemu/prepare-emmc-qemu
@@ -37,6 +37,8 @@
     exit 1
 fi
 
+xzdec -V > /dev/null
+
 set -x
 
 target="$1"