C2SoftHevcEnc: Reduce min supported resolution to 2x2

libhevc encoder library earlier had a restriction on min resolution
supported as 320x128. It now supports upto 2x2.
This commit updates min supported resolution in c2 plugin and as well
in xml files.

Also add supported frame-rate range in xml for c2 soft hevc encoder

Bug: 130537033
Test: atest android.media.cts.MediaCodecCapabilitiesTest#\
testAllAdvertisedVideoEncoderBitrateModes
Test: atest android.media.cts.MediaCodecCapabilitiesTest#\
testAllNonTunneledVideoCodecsSupportFlexibleYUV

Change-Id: I0cfcf3cb3098a2a63c9386a047c702ab3c5c5a32