V4L/DVB (7782): pvrusb2: Driver is no longer experimental

This driver has been in-kernel and reasonably stable for well over a
year.  It is in a stable form and is known to work well.  Remove its
experimental status.
Signed-off-by: NMike Isely <isely@pobox.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/pvrusb2/Kconfig

 config VIDEO_PVRUSB2
 	tristate "Hauppauge WinTV-PVR USB2 support"
-	depends on VIDEO_V4L2 && I2C && EXPERIMENTAL
+	depends on VIDEO_V4L2 && I2C
 	select FW_LOADER
 	select MEDIA_TUNER
 	select VIDEO_TVEEPROM