interconnect: icc-rpm: Use NOC_QOS_MODE_INVALID for qos_mode check

Use NOC_QOS_MODE_INVALID for invalid qos_mode check to improve the
readability.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20211206075808.18124-2-shawn.guo@linaro.org


Signed-off-by: Georgi Djakov <djakov@kernel.org>