zephyr: Update gpio.c to support Zephyr v2.6
zephyr: Update gpio.c to support Zephyr v2.6

Zephyr v2.6 changed the gpio APIs. Use the IS_ZEPHYR_VERSION.

BRANCH=none
BUG=b:190731415
TEST=build brya

Signed-off-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@chromium.org>
Change-Id: Ib0f6192cda63019c19dffcb9529e01b356715e58
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2970987
Reviewed-by: Denis Brockus <6b21e8190fb5e373363fb95271367073a16474ef@chromium.org>

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