mei: add common prefix to hbm function

1. use mei_hbm_ for basic host bus message function
2. use mei_hbm_cl prefix for host bus messages that operation
on behalf of a client

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