glsl: Fail linkage when UBO exceeds GL_MAX_UNIFORM_BLOCK_SIZE.

glsl: Fail linkage when UBO exceeds GL_MAX_UNIFORM_BLOCK_SIZE.

It's not totally clear whether other Mesa drivers can safely cope with
over-sized UBOs, but at least for llvmpipe receiving a UBO larger than
its limit causes problems, as it won't fit into its internal display
lists.

This fixes piglit "arb_uniform_buffer_object-maxuniformblocksize
fsexceed" without regressions for llvmpipe.

NVIDIA driver also fails to link the shader from
"arb_uniform_buffer_object-maxuniformblocksize fsexceed".

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65525

PS: I don't recommend cherry-picking this for Mesa stable, as some app
might inadvertently been relying on UBOs larger than
GL_MAX_UNIFORM_BLOCK_SIZE to work on other drivers, so even if this
commit is universally accepted it's probably best to let it mature in
master for a while.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>