Use C code quantization function for tx_size below 4x4
Use C code quantization function for tx_size below 4x4

This avoids the alignment issue in the SIMD implementation.

Change-Id: I0cfe1f2ef8e1ea866e0c6f32e34c6b22ac5febd2

smarter/aom,luctrudeau/aom,GrokImageCompression/aom,luctrudeau/aom,smarter/aom,smarter/aom,GrokImageCompression/aom,GrokImageCompression/aom,smarter/aom,luctrudeau/aom,smarter/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom