docs: Sample driver to demonstrate how to use Mediated device framework.

The Sample driver creates mdev device that simulates serial port over PCI
card.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

samples/vfio-mdev/Makefile

@@ -0,0 +1,13 @@
+#
+# Makefile for mtty.c file
+#
+KERNEL_DIR:=/lib/modules/$(shell uname -r)/build
+
+obj-m:=mtty.o
+
+modules clean modules_install:
+	$(MAKE) -C $(KERNEL_DIR) SUBDIRS=$(PWD) $@
+
+default: modules
+
+module: modules