cros_config: Change cros_config_read_*sku_info* input array format

The cros_config_read_* have different arguments:
 - ARM (fdt) versions need a list of identifiers and one length arg.
 - X86 versions take a single comma separated list
Meanwhile, probe_frid and other functions take a string array with NULL
in last element.

To unify, we should always use NULL-terminated array and strlfind to
look up list.

BUG=chromium:982692
TEST=emerge-{kukui,octopus,eve} mosys; run 'mosys platform model' on device.

Change-Id: I4bb38062d9b9ce57750d3224656b5c9f88e0c878
Reviewed-on: https://chromium-review.googlesource.com/1697967
Tested-by: Hung-Te Lin <hungte@chromium.org>
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Hsin-Yi Wang <hsinyi@chromium.org>
13 files changed