greybus: es2: fix arpc error message

Add missing le16_to_cpu() to an ARPC error message in the receive path,
and also use %u to print the unsigned id.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>