Use a separate field for the chroma stride

When both luma and chroma are copied to the local buffer (either
due to yuv format conversion, or due to padding), they have got
the same stride, but if chroma is copied while luma is used directly
from the input buffer, they might have different strides.

Therefore add a separate field for chroma stride.

This commit only adds the field, while it still has got the same
value as before.

Change-Id: I0dce97ad4d91cd1d9aba4b4472c6a0de45a314bc
5 files changed