mei: hbm: revamp client connect and disconnection status

1. Return -ENOTTY on client connect if the requested client was not found
 on the enumeration list or the client was internally disabled, in the later
 case FW will return NOT_FOUND.
2. Return -EBUSY if the client cannot be connected because of resource
 contention
3. Change response status enum to have MEI_CL_ prefix
4. Add function to translate response status to a string
for more readable logging

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