In cases where the frame width is not a multiple of 16 the
ARNR filter would go wrong.

In vp8_temporal_filter_iterate_c when updating pointers
at the end of a row of MBs,  the image size was
incorrectly used rather than using Num_MBs_In_Row
times 16 (Y) or 8 (U,V).

This worked when width is multiple of 16 but failed
otherwise.

Change-Id: I008919062715bd3d17c7aa2562ab58d1cb37053a