acerhdf: Adding support for "manual mode"

Some Acer models require an additional command to turn off the fan after
bios mode has been enabled.  Adding new section in bios table to allow
support for those models, by writing an extra "manual mode" register.

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>
acerhdf: Adding support for new models

added following new models:
   * Aspire 5755G
   * AO521
   * AO751h
   * Aspire One 753
   * Extensa 5420
   * Aspire 5315
   * Aspire 5739G
   * TravelMate TM8573T

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>
acerhdf: Use bang-bang thermal governor

acerhdf has been doing an on-off fan control using hysteresis by
post-manipulating the outcome of thermal subsystem trip point handling.
This patch enables acerhdf to use the bang-bang governor, which is
intended for on-off controlled fans.

Cc: Andrew Morton <akpm@linux-foundation.org>
CC: Zhang Rui <rui.zhang@intel.com>
Cc: Andreas Mohr <andi@lisas.de>
Cc: Javi Merino <javi.merino@arm.com>
Acked-and-tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Feuerer <peter@piie.net>
acerhdf: added critical trip point

added critical trip point which represents the temperature limit.
Added return -EINVAL in case wrong trip point is provided.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Mohr <andi@lisas.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Javi Merino <javi.merino@arm.com>
Signed-off-by: Peter Feuerer <peter@piie.net>
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: 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>