mesa: Reject texture-only formats as renderbuffer formats in ES 3

mesa: Reject texture-only formats as renderbuffer formats in ES 3

ES 3 specifies some formats as texture-only (i.e., not available for
renderbuffers).

See the "Required Texture Formats" section (pg 126) of the ES 3 spec.

v2: Allow RED and RG float rendering in core profiles The check used to
be (version > 30) || (compat profile w/extensions).  Just deleting
<version > 30) broke 3.0+ core profiles.

Fixes es3conform's color_buffer_unsupported_format test.

Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>