clk: qcom: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style
in clk-regmap-mux-div.h. 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



Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>