pytests: test_cpuidle: remove governor check

the governor name doesn't stay the same for newer kernels that use a
psci interface. When the cpu-sleep sleep state is available, we can
expect a governor to be in place too.

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>

pytests/test_cpuidle.py

-def test_cpuidle_governor():
-    assert("menu\n" == open("/sys/devices/system/cpu/cpuidle/current_governor_ro").read())
-
-
 def test_cpuidle():
     assert("WFI\n" == open("/sys/devices/system/cpu/cpu0/cpuidle/state0/name").read())
     assert("cpu-sleep\n" == open("/sys/devices/system/cpu/cpu0/cpuidle/state1/name").read())