ilo: Drop the explicit intialization of gaps in TGSI opcodes.

ilo: Drop the explicit intialization of gaps in TGSI opcodes.

The nice thing about the good way of initializing arrays like this is that
you don't need to initialize everything in order, or even everything at
all.  Taking advantage of that only needs a tiny fixup to deal with the
default NULL value of the pointers.

I haven't dropped the initialization of opcodes that exist and are unsupported.