vfio/mdev: make mdev.h standalone includable

Include <linux/device.h> and <linux/uuid.h> so that users of this headers
don't need to do that and remove those includes that aren't needed
any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220923092652.100656-4-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

samples/vfio-mdev/mbochs.c

@@ -21,7 +21,6 @@
  */
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>

samples/vfio-mdev/mdpy.c

@@ -17,7 +17,6 @@
  */
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>

samples/vfio-mdev/mtty.c

@@ -12,7 +12,6 @@
 
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/poll.h>
@@ -20,7 +19,6 @@
 #include <linux/cdev.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
-#include <linux/uuid.h>
 #include <linux/vfio.h>
 #include <linux/iommu.h>
 #include <linux/sysfs.h>