tlv_eeprom: suppress -Wstringop-truncation warning for false positive

tlv_eeprom: suppress -Wstringop-truncation warning for false positive

Suppress this warning:

tlv_eeprom.c:490:17: warning: ‘__builtin_strncpy’ specified bound 256 equals destination size [-Wstringop-truncation]
  490 |                 strncpy(data, strval, MAX_TLV_VALUE_LEN);
      |                 ^

Data is a fixed-length buffer, and no terminating null character is required,
thus this warning is a false positive.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>