V4L/DVB (5640): Fix: em28xx shouldn't be selecting VIDEO_BUF

Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/em28xx/Kconfig

 config VIDEO_EM28XX
 	tristate "Empia EM2800/2820/2840 USB video capture support"
-	depends on VIDEO_V4L1 && I2C && PCI
-	select VIDEO_BUF
+	depends on VIDEO_V4L1 && I2C
 	select VIDEO_TUNER
 	select VIDEO_TVEEPROM
 	select VIDEO_IR