libs/input: make parameter comment style consistent

The Google C++ style guide [0] suggests that parameter name comments
should be of the form `/*paramName=*/value`. This potentially allows
tooling to check that the parameter names are correct, too.

[0]: https://google.github.io/styleguide/cppguide.html#Function_Argument_Comments

Bug: 245989146
Test: atest inputflinger_tests
Change-Id: Id5207b5a621c9a1ac0a46a8b2ff2bbf9aa43e726