glsl: fix the value of gl_MaxFragmentUniformVectors

NOTE: This is a candidate for the 9.1 branch.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/glsl/builtin_variables.cpp

@@ -535,7 +535,7 @@ generate_common_ES_uniforms(exec_list *instructions,
    add_builtin_constant(instructions, symtab, "gl_MaxTextureImageUnits",
 			state->Const.MaxTextureImageUnits);
    add_builtin_constant(instructions, symtab, "gl_MaxFragmentUniformVectors",
-			state->Const.MaxFragmentUniformComponents);
+			state->Const.MaxFragmentUniformComponents / 4);
 
    add_uniform(instructions, symtab, "gl_DepthRange",
 	       state->symbols->get_type("gl_DepthRangeParameters"));