correct a wording

Author: KazuCocoa

appium/webdriver/webdriver.py

@@ -797,7 +797,7 @@ def set_location(self, latitude, longitude, altitude):
 
     @property
     def device_time(self):
-        """Returns the date and time fomr the device
+        """Returns the date and time from the device
         """
         return self.execute(Command.GET_DEVICE_TIME, {})['value']