platform/chrome: cros_ec_lpc: Add support for Google devices using custom coreboot firmware

This patch adds generic device information to the DMI table of
the cros_ec_lpc driver, needed for Chromebooks/boxes using a
custom coreboot firmware.

The DMI info would not contain "Google_*" as BIOS version string,
instead the system vendor string would still be "GOOGLE", so this
seems to be a reasonable match for every Chromebook/box running
a custom firmware.

Signed-off-by: Salvatore Bellizzi <lkml@seppia.net>
Signed-off-by: Vittorio Gambaletta <linuxbugs@vittgam.net>
Signed-off-by: Benson Leung <bleung@chromium.org>