[TF-M] Bug in GNU Arm Embedded toolchain (version 10-2020-q4-major) for TFM

Be aware that the binary release of the GNU Arm embedded toolchain version 10-2020-q4-major has a bug in it that impacts TFM support.

I’ve reported this to the Arm team that works on the toolchain and provided a fix as well. The libgcc/cmse.o code isn’t being properly compiled and thus doesn’t work correctly.

I’ve made the fix in the Zephyr SDK toolchain that provides an Arm embedded build:

https://github.com/zephyrproject-rtos/sdk-ng

Bug fix here:

https://github.com/zephyrproject-rtos/sdk-ng/blob/master/patches/gcc/10.2.0/...

- k