[linux] CSysfsPath: use stat for file exist check

The check by ifstream do fail on files with write only permission.

AMLCodec: use FIFO structure for pts overflow backup

Amlogic hardware decoder can handle up to 31 bit numbers only.
Because of that a pts backup of bit 32 to 64 is needed before send data to the hardware decoder.
By a FIFO deque the backuped pts overflow can be added back to the incoming decoded frame.
On some streams the pts sign changes on the first few frames. A deque buffer almost can fix this.

AMLCodec: ignore m_ptsOverflow on first frame

If pts is negative on first frame the clock get set wrong because of
m_ptsOverflow.

DVDVideoCodecAmlogic::Open: do not skip stream info with 'stills' fra…

…mes if fps != 0

Skip stream if fps == 0. This will fix black screen on DVD/BD-J video menu.

DVDVideoCodecAmlogic::Open: do not skip stream info with 'stills' fra…

…mes if fps != 0

Skip stream if fps == 0. This will fix black screen on DVD/BD-J video menu.

AMLCodec: Use amvecm to handle contrast/brightness

The contrast/brightness controls under /sys/class/video/ don't work on the
newer devices so switch to using the ones under /sys/class/amvecm/ instead

Settings: remove GPU overclock setting as it has been shown to

introduce playback issues when seeking in H265 content.

AMLCodec: do not check free decoder buffer

  The buffer blocks (3 pcs, 512KB for 1080p, 2MB for >= 4k) are choosen
  by frame size and need a frame to get the next free block.

AMLCodec: do not check free decoder buffer

  The buffer blocks (3 pcs, 512KB for 1080p, 2MB for >= 4k) are choosen
  by frame size and need a frame to get the next free block.

Revert "fixed: We should always update stream details from player (fi…

…xes #15584)"

This reverts commit be1ed70.