i915g: Enable instanced drawing.

src/gallium/drivers/i915/i915_screen.c

@@ -178,6 +178,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_TWO_SIDED_STENCIL:
    case PIPE_CAP_VERTEX_ELEMENT_INSTANCE_DIVISOR:
    case PIPE_CAP_BLEND_EQUATION_SEPARATE:
+   case PIPE_CAP_TGSI_INSTANCEID:
       return 1;
 
    /* Unsupported features (boolean caps). */
@@ -185,7 +186,6 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_DEPTH_CLAMP:
    case PIPE_CAP_INDEP_BLEND_ENABLE:
    case PIPE_CAP_INDEP_BLEND_FUNC:
-   case PIPE_CAP_TGSI_INSTANCEID:
    case PIPE_CAP_SHADER_STENCIL_EXPORT:
    case PIPE_CAP_TEXTURE_MIRROR_CLAMP:
    case PIPE_CAP_TEXTURE_SWIZZLE: