[Bug target/64154] enable fipa-ra for Thumb1

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64154

--- Comment #4 from vries at gcc dot gnu.org ---
> I'll file a PR.

PR 64539: '[5 regression] cprop_hardreg does not respect clobbers in C_I_F_U'