cpuidle: Fix finding state with min power_usage

** and Disabled more useless settings (defconfig)

Since cpuidle_state.power_usage is a signed value,
use INT_MAX (instead of -1) to init the local copies
so that functions that tries to find cpuidle states with
minimum power usage works correctly
even if they use non-negative values.

Conflicts:
	drivers/cpuidle/cpuidle.c
	drivers/cpuidle/governors/menu.c

Change-Id: I4538fffc0395460dee550ca1b7aacfb4095c37cb