flewinter: define CONFIG_FAN
flewinter: define CONFIG_FAN

b/181271666 had closed, so define CONFIG_FAN to control fan duty

BUG=b:198371480
BRANCH=main
TEST=make BOARD=felwinter, can control fan via ectool

Signed-off-by: Josh Tsai <b681810fc49463e1e4e60070acf67ed415b3510c@compal.corp-partner.google.com>
Change-Id: I1af02e621d7f4e59309f2f6cb106e916003eb03c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3267670
Reviewed-by: Ko Ko <0cc082a0cd445f866e8a9ee2cb15f4d5dfc36bed@compal.corp-partner.google.com>
Reviewed-by: caveh jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>
Commit-Queue: caveh jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec