IB/hfi1: Rename exp_lock to exp_mutex

The mutex exp_lock in struct hfi1_ctxtdata is used to protect all
Expected TID data of a user context. This patch renames it to exp_mutex
to better reflect its identity and prepare for upcoming patches.

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hfi1/init.c

@@ -368,7 +368,7 @@ int hfi1_create_ctxtdata(struct hfi1_pportdata *ppd, int numa,
 		rcd->numa_id = numa;
 		rcd->rcv_array_groups = dd->rcv_entries.ngroups;
 
-		mutex_init(&rcd->exp_lock);
+		mutex_init(&rcd->exp_mutex);
 
 		hfi1_cdbg(PROC, "setting up context %u\n", rcd->ctxt);