sysv/ms_abi attribute fix, part 2, avoid caching of call used in dataflow

[Ian Lance Taylor]

Jan Hubicka <hubicka@ucw.cz> writes:

> Kenny, perhaps cleaner approach would be to make df_invalidated_by_call
> regs_invalidated_by_call_regset initialized by regcalss's init_regs
> where all the other stuff is initialized.  If this is preferred
> solution, I will prepare updated patch.

I agree that we should do this via init_regs.

Ian