zephyr/ppc_syv682x: add support for frs_en pin
zephyr/ppc_syv682x: add support for frs_en pin

Make syv692x driver generates frs_en member if defined in device tree.

BUG=b:220814055
TEST=1) zmake test
     2) verify the generated ppc_chips array in Krabby
BRANCH=none

Signed-off-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@google.com>
Change-Id: I51a91be0d962bafd1cb3ead44f73a5faade6af09
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3482488
Reviewed-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Commit-Queue: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>
Tested-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>

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