Bring back rockchip-mpp support (upstream repo is now public again)

rockchip-mpp was disabled[1] a while ago because the upstream
repository was temporarily set to private[2] (hidden from the
public). Now the rockchip-mpp repositry is public[3] again and
we can re-enable this feature.

References
----------
[1] https://aur.archlinux.org/cgit/aur.git/commit/?h=ffmpeg-full&id=a224acc3d9b2d35eee6100a60e3df5822d1845dd
[2] https://github.com/HermanChen/mpp/issues/15#issuecomment-690804709
[3] https://github.com/rockchip-linux/mpp/

.SRCINFO

@@ -1,7 +1,7 @@
 pkgbase = ffmpeg-full
 	pkgdesc = Complete solution to record, convert and stream audio and video (all possible features including libfdk-aac)
 	pkgver = 4.3.1
-	pkgrel = 9
+	pkgrel = 10
 	url = https://www.ffmpeg.org/
 	arch = x86_64
 	license = custom: nonfree and unredistributable
@@ -115,6 +115,7 @@ pkgbase = ffmpeg-full
 	depends = xavs
 	depends = xavs2
 	depends = pocketsphinx
+	depends = rockchip-mpp
 	provides = libavcodec.so
 	provides = libavdevice.so
 	provides = libavfilter.so