broadcom: Add vc5 CLIF dumping

broadcom: Add vc5 CLIF dumping

This will be usable with "VC5_DEBUG=cl" on the vc5 driver to stream a CLIF
file (the Broadcom equivalent of i965's AUB) to stderr.  I haven't tested
that this is actually usable with the internal CLIF-consuming tools, but
is close enough as a baseline and is useful for visually inspecting the
command stream.