Make av1_convolve_2d_sr_sse2 support various shift settings
Make av1_convolve_2d_sr_sse2 support various shift settings

Make the convolve_2d_sr_sse2 support all the bit shift tuning
settings in CONFIG_LOWPRECISION_BLEND and off.

Change-Id: I497105d9d7f0a0f9c5edcac55b366825ec13a2ed

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