microblaze: Fix atomic boolean return value.

[alpsayin]

In atomic_compare_and_swapsi, fix boolean return value. Previously, it contained zero if successful and non-zero if unsuccessful.

Fixes Zephyr SDK Issue zephyrproject-rtos/sdk-ng#646.
Patch file taken and applied from: https://github.com/Xilinx/meta-xilinx/blob/master/meta-microblaze/recipes-devtools/gcc/gcc-12/0009-Patch-microblaze-Fix-atomic-boolean-return-value.patch

CC @keith-packard

[stephanosio]

As @keith-packard already pointed out, it would be good to pull in all the Microblaze patches in https://github.com/Xilinx/meta-xilinx/tree/master/meta-microblaze/recipes-devtools/gcc/gcc-12

[alpsayin]

I apologise I disappeared without notice, I've been busy with work.
I'll make use of the holidays now and start applying. I have some catching up to do...

[alpsayin]

Good news is -as far as I could test- all picolibc tests except printf_scanf and test-raise pass.
I believe it's the way I configured the qemu or the way we configured the monitor is causing scanf issues.
I tested with below with https://github.com/alpsayin/picolibc/tree/alpsayin-microblaze-hacks

for test in $(find test -type f -executable -print); do echo $test; ../scripts/run-microblazeel $test ; done

I'll first take a look into what's happening with printf_scanf and test-raise (signal) and then carry on with refactoring all the patches into a (this?) PR.

[alpsayin]

printf_scanf was a non-issue, my mistake. raise issue is as below:

picolibc/picolibc#460

[alpsayin]

Closing in favour of #24