intel: expose ARB_framebuffer_object in the i915 driver.

ARB_fbo no longer disallows mismatched width/height on attachments
(shouldn't be any problem), mixed format color attachments (we only
support 1), and L/A/LA/I color attachments (we already reject them on
965 too).  It requires Gen'ed names (driver doesn't care), and adds
FramebufferTextureLayer (we don't do texture arrays).  So it looks
like we're already in the position we need to be for this extension.

Bug #27468, #32381.

src/mesa/drivers/dri/intel/intel_extensions.c

@@ -80,6 +80,7 @@
 static const struct dri_extension card_extensions[] = {
    { "GL_ARB_draw_elements_base_vertex",  GL_ARB_draw_elements_base_vertex_functions },
    { "GL_ARB_explicit_attrib_location",   NULL },
+   { "GL_ARB_framebuffer_object",         GL_ARB_framebuffer_object_functions},
    { "GL_ARB_half_float_pixel",           NULL },
    { "GL_ARB_map_buffer_range",           GL_ARB_map_buffer_range_functions },
    { "GL_ARB_multitexture",               NULL },
@@ -161,7 +162,6 @@ static const struct dri_extension brw_extensions[] = {
    { "GL_ARB_fragment_program",           NULL },
    { "GL_ARB_fragment_program_shadow",    NULL },
    { "GL_ARB_fragment_shader",            NULL },
-   { "GL_ARB_framebuffer_object",         GL_ARB_framebuffer_object_functions},
    { "GL_ARB_half_float_vertex",          NULL },
    { "GL_ARB_occlusion_query",            GL_ARB_occlusion_query_functions },
    { "GL_ARB_point_sprite", 		  NULL },