fm10k: use spinlock to implement mailbox lock

Lets not re-invent the locking wheel. Remove our bitlock and use
a proper spinlock instead.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
index 4e5e3e6..240772a 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
@@ -1921,6 +1921,9 @@ static int fm10k_sw_init(struct fm10k_intfc *interface,
 	netdev_rss_key_fill(rss_key, sizeof(rss_key));
 	memcpy(interface->rssrk, rss_key, sizeof(rss_key));
 
+	/* Initialize the mailbox lock */
+	spin_lock_init(&interface->mbx_lock);
+
 	/* Start off interface as being down */
 	set_bit(__FM10K_DOWN, interface->state);
 	set_bit(__FM10K_UPDATING_STATS, interface->state);