softpipe: Enable PIPE_CAP_MIXED_COLORBUFFER_FORMATS
It seems softpipe actually supports this. This change enables the following piglits as passing without regressions in the gpu test set:
gl-3.1-mixed-int-float-fbo
gl-3.1-mixed-int-float-fbo int_second
fbo-blending-format-quirks
Changes for deqp:
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.rbo_tex_none_none QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.rbo_tex_none_rbo QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.rbo_tex_none_tex QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.rbo_tex_rbo_none QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.rbo_tex_tex_none QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.tex_rbo_none_none QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.tex_rbo_none_rbo QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.tex_rbo_none_tex QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.tex_rbo_rbo_none QualityWarning -> Pass
dEQP-GLES2.functional.fbo.completeness.attachment_combinations.tex_rbo_tex_none QualityWarning -> Pass
dEQP-GLES3.functional.fbo.completeness.samples.rbo0_rbo0_tex Fail -> Pass
dEQP-GLES3.functional.fbo.completeness.samples.rbo0_tex_none Fail -> Pass
dEQP-GLES3.functional.fbo.completeness.samples.rbo1_rbo1_rbo1 Fail -> Pass
dEQP-GLES3.functional.fragment_out.random.* NotSupported -> Pass
dEQP-GLES31.functional.shaders.builtin_functions.common.frexp.*_fragment Fail -> Pass
dEQP-GLES31.functional.shaders.builtin_functions.common.frexp.*_vertex Fail -> Pass
dEQP-GLES31.functional.shaders.builtin_functions.precision.frexp.*_fragment.* Fail -> Pass
dEQP-GLES31.functional.shaders.builtin_functions.precision.frexp.*_vertex.* Fail -> Pass