Revert "C2SoftHevcEnc: Increase supported resolution to 960x544"

This reverts commit d1f28821.

Reason for revert: Increased resolution may not be supported well
in all platforms. Keeping this at 512x512 for now.

Bug: 152576008
Test: atest android.mediav2.cts.EncoderProfileLevelTest

Change-Id: Iefbcd5df805476e8370894b651d86a8e1803c447