platform/x86: thinkpad_acpi: Correct dual fan probe

There was an issue with the dual fan probe whereby the probe was
failing as it assuming that second_fan support was not available.

Corrected the logic so the probe works correctly. Cleaned up so
quirks only used if 2nd fan not detected.

Tested on X1 Carbon 10 (2 fans), X1 Carbon 9 (2 fans) and T490 (1 fan)

Signed-off-by: Mark Pearson <markpearson@lenovo.com>
Link: https://lore.kernel.org/r/20220502191200.63470-1-markpearson@lenovo.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>