Log: controller: add FSA action flag functions

... instead of set_bit()/clear_bit(), which improves trace messages like:

Bit 0x00000200 set by some_function:100

to:

FSA action flags 0x00000200 (A_DC_TIMER_STOP) for controller set by some_function:100

The new flag functions also replace the register_fsa_action() wrapper. To keep
similar behavior, they log at debug level, rather than the usual trace.