vfio/pci: Remove dev_fmt definition

It currently results in messages like:

 "vfio-pci 0000:03:00.0: vfio_pci: ..."

Which is quite a bit redundant.
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NKevin Tian <kevin.tian@intel.com>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci.c

@@ -9,7 +9,6 @@
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#define dev_fmt pr_fmt
 
 #include <linux/device.h>
 #include <linux/eventfd.h>