[mac] enable wake-up frame periodic sniffing #26

Job	Run time
packet-verification-1-1-on-1-4	12m 20s
packet-verification-low-power	10m 49s
thread-1-4-gcc-m32	8m 16s
thread-1-4-gcc-m64	8m 30s
thread-1-4-clang-10-m32	7m 44s
thread-1-4-clang-10-m64	7m 27s
channel-manager-csl	3m 17s
expects	10m 39s
thread-1-4-posix	10m 0s
upload-coverage	1s
	1h 19m 3s

Provide feedback