glx: correctly mask the drawableType for GLX_ARB_fbconfig_float
glx: correctly mask the drawableType for GLX_ARB_fbconfig_float

The comment/spec says - only for pbuffer drawables, while the code
clears the window/pixmap bit. Practise what you preach and apply the
trivial tweak. In practise this should not cause functional change.

Signed-off-by: Emil Velikov <f20878473f414da183da19ee25c8722cc1d711e4@collabora.com>
Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com>
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>


metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler