intel_th: Use the correct style for SPDX License Identifier
This patch corrects the SPDX License Identifier style
in header files related to Drivers for Intel(R) Trace Hub
controller.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used)
Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46