anv: reduce maxFragmentInputComponents

anv: reduce maxFragmentInputComponents

If the application asks for the maximum number of fragment input
components (128), use all of them plus some builtins that are
passed in the VUE, then we exceed the maximum number of used VUE
slots (32) and we break one assert that checks this limit.

Also, with separate shader objects, we add CLIP_DIST0, CLIP_DIST1
builtins in brw_compute_vue_map() because we don't know if
gl_ClipDistance is going to be read/write by an adjacent stage.

Fixes VK-GL-CTS CL#2569.

Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>