arch: arm: aarch32: clear CONTROL.FPCA for every CPU that has a FPU

Upon reset, the CONTROL.FPCA bit is, normally, cleared. However,
it might be left un-cleared by firmware running before Zephyr boot,
for example when Zephyr image is loaded by another image.
We must clear this bit to prevent errors in exception unstacking.
This caused stack offset when booting from a build-in EFM32GG bootloader

Fixes #22977

Signed-off-by: Luuk Bosma <l.bosma@interay.com>