contrib: use ffmpeg v4.2.2 for macOS

ffmpeg v4.3 cause high CPU usage on macOS

Change-Id: I51c85036e90e4b0fb7ebb3a9810da52c8ee4b65f

contrib/src/ffmpeg/SHA512SUMS

+ifdef HAVE_MACOSX
+df0393b9dbee05f64f80ff98512ec153c78ccca9f8ea170301703cd0b92fb68c91c8113ab8a2ecb161ac465544edefe29dd1965e6959694f8728fee529606665  ffmpeg-n4.2.2.tar.gz
+else
 b00ca3b77e9c9a4ee69a50283471bf136c1a35a837982aa886e9c50c546e48a6b5ea2acd1e183990eefe6c32fb1d5504684925abb7d8fa4f80b7e53864647c6c  ffmpeg-n4.3.tar.gz
+endif

contrib/src/ffmpeg/rules.mak

+ifdef HAVE_MACOSX
+FFMPEG_HASH := n4.2.2
+else
 FFMPEG_HASH := n4.3
+endif
+
 FFMPEG_URL := https://git.ffmpeg.org/gitweb/ffmpeg.git/snapshot/$(FFMPEG_HASH).tar.gz
 
 PKGS+=ffmpeg