On Armv8 targets, the PSA interface on the non-secure side only
requires mutexes, thus we remove other RTOS overrides to reduce
memory usage in general use cases.

TF-M and PSA test applications require more RTOS resources, and
they have their own configurations defined in
mbed-os-tf-m-regression-tests.

This commit also adds missing configuration for ARM_MUSCA_B1.