quark_se_ss: Remove enter_arc_state and use QMSI functions

This commit removes the local implementation of enter_arc_state, where
the ARC is instructed to sleep, using instead the QMSI 1.4 functions.

Change-Id: Id489ad53851be50fc5e50add698891fcfaef3abe
Signed-off-by: Juan Solano <juanx.solano.menacho@intel.com>