igb: Fix for lockdep issue in igb_get_i2c_client

This patch fixes a lockdep warning in igb_get_i2c_client by
refactoring the initialization and usage of the i2c_client
completely.  There is no on the fly allocation of the single
client needed today.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index d27edbc..2515140 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -447,7 +447,7 @@
 #endif
 	struct i2c_algo_bit_data i2c_algo;
 	struct i2c_adapter i2c_adap;
-	struct igb_i2c_client_list *i2c_clients;
+	struct i2c_client *i2c_client;
 };
 
 #define IGB_FLAG_HAS_MSI		(1 << 0)