fan: fix fanduty console command
fan: fix fanduty console command

This fixes how the fanduty console command parses its arguments. The
original parsing would use the fan number as the duty cycle percentage
when two arguments were given on a single fan system. Two arguments are
now always treated as (fan number, duty cycle). On a single fan system,
the fan number may be omitted. Additional arguments are rejected.

BRANCH=none
BUG=none
TEST=verified fanduty console command controls fan

Change-Id: Ib7f0141e698d80957a6ac7b770602dcf049aafbc
Signed-off-by: Caveh Jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2689497
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Commit-Queue: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

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