Update header inclusions to follow IWYU (Include What You Use)
principle.
Note that kernel.h is discouraged to be included as it's written
at the top of that file.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>