elm: set SPI2 interface to low in S5
elm: set SPI2 interface to low in S5

BUG=chrome-os-partner:51708
BRANCH=none
TEST=poweroff elm, measure PP3300 and voltage is ~ 0.05V.

Change-Id: I17088bf15a97eb7337abbe773897eaf298086752
Signed-off-by: Koro Chen <a316d89c8b5185b78cc2c56b469d422d2a73588f@mediatek.com>
Reviewed-on: https://chromium-review.googlesource.com/344492
Reviewed-by: Rong Chang <3a05493f7adfb36d203f663b3bc2ba30e9d6284f@chromium.org>

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