ec/google/chromeec: add support for retrieving OEM name

OEM name can be stored in CBI. This change can support for fetching
the OEM name from CBI.

BUG=b:118798180
TEST=Verified to get data from CBI

Change-Id: I4938c4d60fcad9e1f43ef69cc4441d1653de7e24
Signed-off-by: Wisley Chen <wisley.chen@quantatw.com>
Reviewed-on: https://review.coreboot.org/29497
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

src/ec/google/chromeec/ec_commands.h

@@ -4781,6 +4781,7 @@ enum cbi_data_tag {
 	CBI_TAG_OEM_ID = 1,        /* uint8_t */
 	CBI_TAG_SKU_ID = 2,        /* uint8_t */
 	CBI_TAG_DRAM_PART_NUM = 3, /* variable length ascii, nul terminated. */
+	CBI_TAG_OEM_NAME = 4,      /* variable length ascii, nul terminated. */
 	CBI_TAG_COUNT,
 };