egl: EXT_pixel_format_float plumbing

egl: EXT_pixel_format_float plumbing

Patch adds support and capability to match with new surface attribute,
component type. Currently no configs with floating point type are exposed.

With this change, following dEQP test starts to pass:

   dEQP-EGL.functional.choose_config.color_component_type_ext.dont_care
   dEQP-EGL.functional.choose_config.color_component_type_ext.fixed
   dEQP-EGL.functional.choose_config.color_component_type_ext.float

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>