fate: png-suite

Every supported format is converted to RGB.
avcodec: Suppress deprecation warnings from DTG code scheduled for removal
fate: Only generate tests/pixfmts.mak if some pixfmts fate test is run
Merge commit '086a541857812b2e0435db38fbabfddc7d19e53c'

* commit '086a541857812b2e0435db38fbabfddc7d19e53c':
  fate: png-suite

Conflicts:
	tests/fate/image.mak

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '990e2f3555bb0adae122d3599938ddcfee46e2d1'

* commit '990e2f3555bb0adae122d3599938ddcfee46e2d1':
  avcodec: Suppress deprecation warnings from DTG code scheduled for removal

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'eee813eec7d3c0b0689f80665d3f796401742935'

* commit 'eee813eec7d3c0b0689f80665d3f796401742935':
  fate: Only generate tests/pixfmts.mak if some pixfmts fate test is run

Merged-by: Michael Niedermayer <michaelni@gmx.at>
lavd/avfoundation: Add device category.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>