!UPSTREAM: i965/gen7: merge defines for 3DSTATE{VS,GS} DW2

Dword 2 of all 3DSTATE commands is the same, so there's no need tohave
separate defines for it.  This will allow us to unify some of the
state setup code.

TODO:
- Unify with WM
- Move earlier in series
!UPSTREAM: i965/gen7: Refactor VS state upload code in preparation for GS.

TODO: move earlier.
!UPSTREAM: Fix gen7_gs_state.c
fixup! !UPSTREAM: i965/gen7: Refactor VS state upload code in preparation for GS.
fixup! !UPSTREAM: Fix gen7_gs_state.c
fixup! !UPSTREAM: i965/gen7: Refactor VS state upload code in preparation for GS.