ok this is tricky: an extra parameter has to be passed into sv_insn_t::remap

ok this is tricky: an extra parameter has to be passed into sv_insn_t::remap

the reason is that the remap has to know if the register being
remapped is an int or a float.  the place where that is known
is at *decode* time... and that means that id_regs.py has to
look that up and pass it on (in a #define REGS_PATTERN).
the reason it is passed in as a pattern is so that svn_insn_t rd/rs1-3
have access to the information that is needed