gcc: enable big-endian toolchain for armv7-R

[ntavish]

No description provided.

[ntavish]

Hi @stephanosio thanks for re-triggering the CI.

Also, what would be required to get this merged? I can do some basic testing, but unfortunately I don't have a working port for a cortex-r5 big-endian with zephyr main branch right now (working on it). I am planning to start working on adding support for TMS570 upstream, and this is required for that.

gcc PR: zephyrproject-rtos/gcc#33
zephyr: zephyrproject-rtos/zephyr#73563

[sigmundklaa]

@ntavish If you are interested, I have done some work for supporting TMS570LS1224 at https://github.com/OrbitNTNU/zephyr-hw. I have been planning to push it to upstream, if I ever end up finishing it. Let me know if you would like to collaborate!

[rahul-arasikere]

I too have been looking to working on a port of RM57Lx series here on a best effort basis: https://github.com/rahul-arasikere/zephyr/tree/add-rm57lx-support. Haven't done enough of a port to start testing however.

[stephanosio]

Rebased and updated gcc sha.