Fix cpufreg_go to use adb -s

cpufreq_go used the plain adb, this changes it to use $adb,
which is set to adb -s if -s was passed, allowing the go test
to run when multiple devices are connected.

Bug: 72652287
Test: manual
Change-Id: Iffd658e9f1f99cbe992a5e1a5a07adc70d334653
1 file changed