shader: TXQ: Don't emit swizzle if we query the size of a buffer
The buffer size is not an vector, and consequently we can't add a swizzle operator. (This was probably the reason why the write mask was only emmited when the it was larger then 1 before).
Fixes: 70dedae4 shader: TXQ: also emit a write mask if only one bit is set.
Signed-off-by: Gert Wollny gert.wollny@collabora.com