- Save the FPU registers into the tcb so they don't get lost if the stack
frame for xcp.regs moves (as it does)
- Handle interger and FPU register save/load separately
- Integer registers are saved/loaded always, like before
- FPU registers are only saved during a context switch:
- Save ONLY if FPU is dirty
- Restore always if FPU has been used (not in FSTATE_OFF, FSTATE_INIT)
- Remove all lazy-FPU related logic from the macros, it is not needed
35c27b5a9a