mesa: Avoid out-of-bounds stack read via _mesa_Materiali
mesa: Avoid out-of-bounds stack read via _mesa_Materiali

MATERIALFV may end up reading up to 4 floats from the passed parameter.

This should really set a GL_INVALID_ENUM error in the cases where it
matters, but does anybody really care?

Found by ASAN in piglit gl-1.0-beginend-coverage.

v2: fix a trivial compiler warning

Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com> (v1)
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com> (v1)

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler