nv30, nv40: non-trivially partially unify nv[34]0_shader.h

nv30, nv40: non-trivially partially unify nv[34]0_shader.h

shader.h is similar, except for the following differences:
1. The instruction sets are not exactly the same, but mostly similar
2. Vertex program fields are in different bit positions

This patch unifies all parts of nv[34]0_shader.h except the vertex
program fields.

Vertex opcodes are also changed so that the constant names includes
SCA if it is a scalar opcode and VEC if it is a vector opcode.