Defer triggering notifyLidSwitchChanged() until the system is ready.

Before the system is ready getSwitchState() returns KEY_STATE_UNKNOWN
for the lid switch causing the initial lidOpen value to be false on boot
even if the lid is currently open. This defers the triggering of any
callbacks registered before the system is ready to ensure that the
initial callback value is correct.

Bug: 159401801
Test: Manual - ensure first callback value matches lid state on boot.
Change-Id: I9351312e5ecf8b1984ae11a47ed9b89dab1aa07f