i965: Delete "fast color clear unsupported" performance warning.

i965: Delete "fast color clear unsupported" performance warning.

Applications frequently clear to colors other than 0.0 or 1.0, which
prevents us from doing fast color clears.  In that case, we issue this
performance warning on basically every glClear call, resulting in so
much spam that it's nearly impossible to see any other messages.

Plus, I don't think it's useful.  We aren't suggesting a better way to
do what the application developers want---we're just telling them it
would be faster to do something they don't want.

Driver developers have no control over the clear color, so this message
is totally useless to them.

A better alternative to get this sort of information is to use
INTEL_DEBUG=blorp, which tells you whether color clears were fast,
simd16 repdata, or slow.

v2: Rebase on has_color_component changes.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>