mithrax: Update RGBKBD type to 4-zones-4-LEDs
mithrax: Update RGBKBD type to 4-zones-4-LEDs

RGBKBD type variable is set to 4-zones-15-LEDs, update it to the correct
value of 4-zones-4-LEDs. This is because it only has four addressable
LED IDs (4 zones) even though it has 15 physical LEDs.

BUG=b:239653506
BRANCH=none
TEST=make BOARD=mithrax -j

Signed-off-by: Parth Malkan <c3d09dcbffc3a0a63125afed46f55e5cbf5bb3a9@google.com>
Cq-Depend: chromium:3794617, chromium:3795088
Change-Id: I5d3572c48869594fe5e5744dedc6938905d4ecd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3794616
Reviewed-by: YH Lin <a608809fda0b3a5e5ffc78f5b79106a21e96e6dd@chromium.org>

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