When we bring up the Valhall compiler in Mesa, we will like to have a
disassembler in native code, so we shouldn't write our disassembler in
Python. Instead, we write a disassembler generator in Python with mako
templates, which will produce a va_disasm_instr entrypoint from the
architecture defined in ISA.xml and valhall.py.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>