i965/vec4/gen6: fix exec_size for instructions with width of 4 in generate_gs_svb_write()
i965/vec4/gen6: fix exec_size for instructions with width of 4 in generate_gs_svb_write()

Signed-off-by: Samuel Iglesias Gonsalvez <b753b212f30aed827c3eea2e437609dc37310153@igalia.com>
Reviewed-by: Topi Pohjolainen <749697f19798b7f640b17221fd283b903825f071@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler