misc/pvpanic: change header file sort style

Make header files alphabetical order.

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>