acerhdf: minor clean up

  * renamed bios_settings_t to bios_settings, as it is no typedef
  * replaced "unsigned char" by u8 in bios_settings struct for better
    readability.

Cc: platform-driver-x86@vger.kernel.org
Cc: Darren Hart <dvhart@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Mohr <andi@lisas.de>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Feuerer <peter@piie.net>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>