Add detection support for the Winbond W83977AF as found in the Advantech PCM-5820 board (confirmed by Erwan Velu <erwan@seanodes.com> on IRC). Trivial (and tested) patch. Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de> Acked-by: Uwe Hermann <uwe@hermann-uwe.de>