fm10k: mark unused parameters with __always_unused

Several functions in the fm10k driver have specific function templates,
as they are used as function pointers. The parameters in these functions
are not always used. Explicitly mark unused parameters with the
__always_unused macro, so that the compiler will not warn about them
when building with the -Wunused-parameter warning enabled.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>