Refactor av1_txfm1d_sse4.h
Refactor av1_txfm1d_sse4.h

1) avoid code duplication
2) Add const
3) remove unused function declarations
4) Add Copyright

Change-Id: Ibb8ba8ee4d49b44a0743e4f5cc605c51279c831e

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom