drm/nouveau/bios/fan: hardcode the fan mode to linear

This is an oversight that made use of the trip-point-based fan managenent on
cards that never expose those. This led the fan to stay at fan_min.

Fortunately, the emergency code would kick when the temperature would reach
90°C.

Reported-by: Tom Englund <tomenglund26@gmail.com>
Tested-by: Tom Englund <tomenglund26@gmail.com>
Signed-off-by: Martin Peres <martin.peres@free.fr>
Tested-by: Daemon32 <lnf.purple@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92126
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/nouveau/nvkm/subdev/bios/fan.c

@@ -83,6 +83,7 @@ nvbios_fan_parse(struct nvkm_bios *bios, struct nvbios_therm_fan *fan)
 			fan->type = NVBIOS_THERM_FAN_UNK;
 		}
 
+		fan->fan_mode = NVBIOS_THERM_FAN_LINEAR;
 		fan->min_duty = nvbios_rd08(bios, data + 0x02);
 		fan->max_duty = nvbios_rd08(bios, data + 0x03);