[Bug target/113948] Switch rx to LRA

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113948

--- Comment #2 from Oleg Endo <olegendo at gcc dot gnu.org> ---
-mlra option has been around on RX for a while.  I've using GCC 8 as production
compiler on a larger firmware.

Adding -mlra to the build will make the thing get stuck during linking (using
LTO) somewhere, looks like it gets stuck in some infinite loop somewhere.