mei: revamp hbm state machine

1. Rename init_clients_state to hbm_state and use
MEI_HBM_ prefix for HBM states

2. Remove recvd_msg and use hbm state for synchronizing
hbm protocol has successful start.
We can wake up the hbm event from start response handler
and remove the hack from the interrupt thread

3. mei_hbm_start_wait function encapsulate start completion
waiting

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>