mei: revamp me client search function

me client search functions returns index
into me_client array according me client id
or me client uuid.

1. Add common prefix for the functions mei_me_cl_<>
2. create new function mei_me_cl_by_id that wraps open
 coded loops scattered over the code
3. rename mei_find_me_client_index to  mei_me_cl_by_uuid
4. rename mei_find_me_client_update_filext  to
 mei_me_cl_update_filext and updates its parameter names

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