Replace C/SIMD switch function tables with dsp_rtcd aliases
Created by: JackZhouVCD
Reincarnate of #524.
This helps simplify the codebase by removing all function tables that are used to pick implementations (c vs simd mostly) and rewriting them in aom_dsp_rtcd.h. Also removes unused asm_type parameters in functions.
This is only updated for commit on master 6012f53c. Please @ me or let me know when this PR goes under review so I can work on making it updated