MLK-21941: imx-hdp-cec: change CEC_TX_STATUS_ERROR to NACK

MLK-21941: imx-hdp-cec: change CEC_TX_STATUS_ERROR to NACK

With commit cd7b7f509cd0 ("media: cec: check for non-OK/NACK
conditions while claiming a LA")

When set the LA, the cec stack try to transmit the message "0x55"
(5 is LA) before configure the LA, and check the return value
But our cec driver alway return ERROR, which cause the setting of
LA failure, so change the return value to be NACK.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>