platform/chrome: cros_ec_lpc: Fix error code in cros_ec_lpc_mec_read_bytes()

platform/chrome: cros_ec_lpc: Fix error code in cros_ec_lpc_mec_read_bytes()

We changed these functions to returning negative error codes, but this
first error path was accidentally overlooked.  It leads to a Smatch
warning:

    drivers/platform/chrome/cros_ec_lpc.c:181 ec_response_timed_out()
    error: uninitialized symbol 'data'.

Fix this by returning the error code instead of success.

Fixes: 68dbac0a58ef ("platform/chrome: cros_ec_lpc: MEC access can return error code")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/e0b43fb5-ecc8-4fb4-9b76-c06dea8cc4c4@moroto.mountain
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>