glsl: Check earlier for MaxTextureImageUnits and MaxImageUniforms

glsl: Check earlier for MaxTextureImageUnits and MaxImageUniforms

Currently the linker do all the work then check for the limits, which
means num_textures and num_images in shader_info may have to store more
than the limit.  This breaks down now since shader_info was packed and
doesn't expect to store larger invalid values.

To fix this, pull the check before we set the counts in shader_info.
Add necessary plumbing to make sure we bail once those errors are
found.

Fixes: 84a1a2578da ("compiler: pack shader_info from 160 bytes to 96 bytes")
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>