[Bug target/64305] [SH] Add support for fschg insn and 64 bit FP moves

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64305

--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Also related: PR 29969, which could be done once FPSCR.SZ mode switching is
there.