panfrost: Initialise the blend equation in create_blend_state
Valgrind still complains about uninitialised values, but tests don't flake anymore.
Fixes flakes in dEQP-GLES3.functional.fragment_out.*
Valgrind still complains about uninitialised values, but tests don't flake anymore.
Fixes flakes in dEQP-GLES3.functional.fragment_out.*