iavf: simplify mutex_trylock+sleep loops

This pattern appears in two places in the iavf source code:
  while (!mutex_trylock(...))
      usleep_range(...);

That's just mutex_lock with extra steps.
The pattern is a leftover from when iavf used bit flags instead of
mutexes for locking. Commit 5ac49f3c ("iavf: use mutexes for locking
of critical sections") replaced test_and_set_bit with !mutex_trylock,
preserving the pattern.

Simplify it to mutex_lock.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231027175941.1340255-3-jacob.e.keller@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -3011,8 +3011,7 @@ static void iavf_reset_task(struct work_struct *work)
 		return;
 	}
 
-	while (!mutex_trylock(&adapter->client_lock))
-		usleep_range(500, 1000);
+	mutex_lock(&adapter->client_lock);
 	if (CLIENT_ENABLED(adapter)) {
 		adapter->flags &= ~(IAVF_FLAG_CLIENT_NEEDS_OPEN |
 				    IAVF_FLAG_CLIENT_NEEDS_CLOSE |
@@ -5065,8 +5064,7 @@ static int __maybe_unused iavf_suspend(struct device *dev_d)
 
 	netif_device_detach(netdev);
 
-	while (!mutex_trylock(&adapter->crit_lock))
-		usleep_range(500, 1000);
+	mutex_lock(&adapter->crit_lock);
 
 	if (netif_running(netdev)) {
 		rtnl_lock();