zephyr: cros_cbi remove unused cached_ssfc
zephyr: cros_cbi remove unused cached_ssfc

The cros,cbi driver was found to contain a bug. During
CBI_SSFC_INIT_DEFAULT_ID() the static cached_ssfc variable was being
initialized. While all the functions using the ssfc values were using
the ones stored in the device's data struct. This means that the case
statements generated were always returning 0 for every case.

BRANCH=none
BUG=b:202789410
TEST=zmake configure --test zephyr/test/drivers

Signed-off-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@google.com>
Change-Id: Icac1491c72e95e4700ce696f91f2cfaf56e0ebff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3218464
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>

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