fixup! !UPSTREAM: i965: Combine 4 boolean args of brw_urb_WRITE into a flags bitfield.
squash! !UPSTREAM: i965: Add an opcode for doing a URB write with an offset from a register (needed for GS).

No more need to fixup alignment
i965/gen7: Allow URB_WRITE_HWORD channel masks to be used.

Previously, brw_urb_WRITE() would unconditionally override the channel
masks in URB_WRITE_HWORD to 0xff (indicating that all channels should
be written to the URB).

For geometry shaders, we need the ability to set the channel masks
programatically, so create a flag to prevent brw_urb_WRITE() from
overriding them.
!UPSTREAM: i965/gs: Make EndPrimitive() work with >32 vertices

TODO:
- Make it work with >128 vertices
- Move to appropriate place in series