message: ocl: don't use vload4 for 3 channel images
diff: @@ -160,6 +160,7 @@ enum
  #define CAT(x, y) __CAT(x, y)
  #define DATA_TYPE_4 CAT(DATA_TYPE, 4)
  +#define DATA_TYPE_3 CAT(DATA_TYPE, 3)
  ///////////////////////////////////// RGB <-> GRAY //////////////////////////////////////
  @@ -182,7 +183,7 @@ __kernel void RGB2Gray(__global const uchar * srcptr, int src_step, int src_offs
  {
  __global const DATA_TYPE* src = (__global const DATA_TYPE*)(srcptr + src_index);
  __global DATA_TYPE* dst = (__global DATA_TYPE*)(dstptr + dst_index);
  - DATA_TYPE_4 src_pix = vload4(0, src);
  + DATA_TYPE_3 src_pix = vload3(0, src);
  #ifdef DEPTH_5
  dst[0] = fma(src_pix.B_COMP, B2YF, fma(src_pix.G_COMP, G2YF, src_pix.R_COMP * R2YF));
  #else
  @@ -256,7 +257,7 @@ __kernel void RGB2YUV(__global const uchar* srcptr, int src_step, int src_offset
  {
  __global const DATA_TYPE* src = (__global const DATA_TYPE*)(srcptr + src_index);
  __global DATA_TYPE* dst = (__global DATA_TYPE*)(dstptr + dst_index);
  - DATA_TYPE_4 src_pix = vload4(0, src);
  + DATA_TYPE_3 src_pix = vload3(0, src);
  DATA_TYPE b = src_pix.B_COMP, g = src_pix.G_COMP, r = src_pix.R_COMP;
  #ifdef DEPTH_5
  