glsl: Don't emit spurious errors for constant indexes of the wrong type

glsl: Don't emit spurious errors for constant indexes of the wrong type

Previously the shader

uniform float x[6];
void main() { gl_Position.x = x[1.0]; }

would have generated the errors

0:2(33): error: array index must be integer type
0:2(36): error: array index must be < 6

Now only

0:2(33): error: array index must be integer type

will be generated.

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