mips msa vp9 updated convolve horiz, vert, hv, copy, avg module

Updated sources according to improved version of common MSA macros.
Enabled respective convolve MSA hooks and tests.
Overall, this is just upgrading the code with styling changes.

Change-Id: If5ad6ef8ea7ca47feed6d2fc9f34f0f0e8b6694d
9 files changed