aco: Remove 0 data components from image stores.

aco: Remove 0 data components from image stores.

Image stores always write a full texel.
The hardware writes zero for components not included in dmask.

Totals from 387 (0.29% of 134913) affected shaders: (GFX10.3)
VGPRs: 17216 -> 17136 (-0.46%)
CodeSize: 1987652 -> 1981504 (-0.31%)
MaxWaves: 9054 -> 9058 (+0.04%)
Instrs: 361883 -> 361115 (-0.21%); split: -0.21%, +0.00%
Latency: 5383187 -> 5381227 (-0.04%); split: -0.04%, +0.00%
InvThroughput: 1373830 -> 1372097 (-0.13%)
VClause: 9031 -> 9038 (+0.08%); split: -0.04%, +0.12%
Copies: 25923 -> 25153 (-2.97%); split: -2.98%, +0.01%
PreVGPRs: 14643 -> 14555 (-0.60%)

Signed-off-by: Georg Lehmann <dadschoorse@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14986>