glsl: Relax GLSL 1.10 float suffix error to a warning.

glsl: Relax GLSL 1.10 float suffix error to a warning.

Float suffixes are allowed in all subsequent GLSL specifications, and
it's obvious what the user meant if they specify one. Accept it with a
warning to avoid breaking applications, like Planeshift (although it
looks like between 0.6.1 and 0.6.3 they might have removed the suffixes
from their shaders).

Reviewed-by: Lars Hamre <chemecse@gmail.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>