platform/chrome: cros_ec_spi: Always add of_match_table

platform/chrome: cros_ec_spi: Always add of_match_table

The Chrome OS EC driver attaches to devices using the of_match_table
even when ACPI is the underlying firmware. It does this using the
magic PRP0001 ACPI HID, which tells ACPI to go find an OF compatible
string under the hood and match on that.

The cros_ec_spi driver needs to provide the of_match_table regardless
of whether CONFIG_OF is enabled or not, since the table is used by
ACPI for PRP0001 devices.

Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>