staging: lustre: ptlrpc: update MODULE_PARAM_DESC in ptlrpcd.c

staging: lustre: ptlrpc: update MODULE_PARAM_DESC in ptlrpcd.c

Update max_ptlrpcds module parameter descriptions to let
users know its obsolete. Change cpt to CPT for the module
parameter description ptlrpcd_per_cpt_max so it matches
documentation.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8890
Reviewed-on: https://review.whamcloud.com/24065
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>