Disable rockchip mpp

Upstream repository for rockchip mpp is gone.

It was at: https://github.com/rockchip-linux/mpp/

I could not find any upstream word about it. The Rockchip Wiki
still points to this repository, without saying if it was really
dropped or moved to another place.

Due to this, new users now cannot build rockchip-mpp package.
Disabling it so new users can build ffmpeg-full.

PKGBUILD

@@ -7,7 +7,7 @@ _svt_vp9_ver='0.2.2'
 
 pkgname=ffmpeg-full
 pkgver=4.3.1
-pkgrel=5
+pkgrel=6
 pkgdesc='Complete solution to record, convert and stream audio and video (all possible features including libfdk-aac)'
 arch=('x86_64')
 url='https://www.ffmpeg.org/'
@@ -30,7 +30,6 @@ depends=(
     # AUR:
         'chromaprint-fftw' 'davs2' 'flite1-patched' 'libklvanc-git' 'openh264'
         'libopenmpt-svn' 'shine' 'vo-amrwbenc' 'xavs' 'xavs2' 'pocketsphinx'
-        'rockchip-mpp'
 )
 makedepends=(
     # official repositories:
@@ -205,7 +204,7 @@ build() {
         --enable-nvdec \
         --enable-nvenc \
         --enable-omx \
-        --enable-rkmpp \
+        --disable-rkmpp \
         --enable-v4l2-m2m \
         --enable-vaapi \
         --enable-vdpau