Staging: iio: Fix file header to match standards

Fix file header to match Linux Kernel style. Remove Free Software
Foundation reference to silence the checkpatch.pl warning.
Add driver description and correct spelling mistakes.
Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/magnetometer/hmc5843_core.c

-/*  Copyright (C) 2010 Texas Instruments
-    Author: Shubhrajyoti Datta <shubhrajyoti@ti.com>
-    Acknowledgement: Jonathan Cameron <jic23@kernel.org> for valuable inputs.
-
-    Support for HMC5883 and HMC5883L by Peter Meerwald <pmeerw@pmeerw.net>.
-
-    Split to multiple files by Josef Gajdusek <atx@atx.name> - 2014
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
+/*
+ * Device driver for the the HMC5843 multi-chip module designed
+ * for low field magnetic sensing.
+ *
+ * Copyright (C) 2010 Texas Instruments
+ *
+ * Author: Shubhrajyoti Datta <shubhrajyoti@ti.com>
+ * Acknowledgment: Jonathan Cameron <jic23@kernel.org> for valuable inputs.
+ * Support for HMC5883 and HMC5883L by Peter Meerwald <pmeerw@pmeerw.net>.
+ * Split to multiple files by Josef Gajdusek <atx@atx.name> - 2014
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
 
 #include <linux/module.h>
 #include <linux/regmap.h>