platform/x86: intel-vbtn: Remove redundant inclusions

Some headers are not needed since the driver can be built as module.
Remove them.

While here, sort headers alphabetically.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>