i965/vec4: emit correctly load_inputs for 64bit data

i965/vec4: emit correctly load_inputs for 64bit data

For dvec3 and dvec4 types, a single GRF do not have enough space to
allocate two inputs from two different vertices (SIMD4x2).

So the GRF only contains first two components for the two vertices, and
the next GRF has the remaining components.

We want to put all the components for the same vertex in the same
register. Thus, we do a shuffle to reorder the data.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>