host: fix typo which broke I2C scanning

Author: Qyriad

host/greatfet/interfaces/i2c_bus.py

@@ -122,7 +122,7 @@ def scan(self):
             in response for valid/invalid addresses.
         """
 
-        responses = self.api.i2c.scan()
+        responses = self.api.scan()
         write_responses = responses[:16]
         read_responses = responses[16:]
         responses = []