Input: edt-ft5x06 - convert to use SPDX identifier

Reduce size of duplicated comments by switching to use SPDX identifier.

No functional change.

While here, correct MODULE_LICENSE() string to be aligned with license text.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>