mtd: nand: tango: Add standard legalese header

Provide proper copyright notice and license information.

---
I originally didn't provide this information because I thought MODULE_AUTHOR defined the copyright holder, and MODULE_LICENSE defined the license. (So I figured the header was redundant.)

---
 drivers/mtd/nand/tango_nand.c | 8 ++++++++
 1 file changed, 8 insertions(+)

index 7ed35348993e..cc23db64f0ca 100644
@@ -1,3 +1,11 @@
+/*
+ * Copyright (C) 2016 Sigma Designs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/clk.h>

2.9.0

It may be redundant, but (IANAL) I expect the macros are more interesting to machines (which can do things like handle GPL vs. non-GPL symbols, and print out nice 'modinfo') and maybe programmers (who are often more like machines than lawyers) than to lawyers.