macintosh/ams-input: Use true and false for boolean values

Assign true or false to boolean variables instead of an integer value.

This issue was detected with the help of Coccinelle
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Michael Hanselmann <public@hansmi.ch>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/macintosh/ams/ams-input.c

@@ -91,7 +91,7 @@ static int ams_input_enable(void)
 		return error;
 	}
 
-	joystick = 1;
+	joystick = true;
 
 	return 0;
 }
@@ -104,7 +104,7 @@ static void ams_input_disable(void)
 		ams_info.idev = NULL;
 	}
 
-	joystick = 0;
+	joystick = false;
 }
 
 static ssize_t ams_input_show_joystick(struct device *dev,