fixed the PerChannel functions in output_sse.h
fixed the PerChannel functions in output_sse.h

petewarden/gemmlowp,google/gemmlowp,maciekcc/gemmlowp,maciekcc/gemmlowp,google/gemmlowp,petewarden/gemmlowp,google/gemmlowp,maciekcc/gemmlowp,petewarden/gemmlowp,petewarden/gemmlowp,google/gemmlowp