net: mvneta: use proper rxq_number in loop on rx queues

When adding the RX queue association with each CPU, a typo was made in
the mvneta_cleanup_rxqs() function. This patch fixes it.

[gregory.clement@free-electrons.com: add commit log and fixes tag]
Cc: stable@vger.kernel.org
Fixes: 2dcf75e2

 ("net: mvneta: Associate RX queues with each CPU")
Signed-off-by: Yelena Krivosheev <yelena@marvell.com>
Tested-by: Dmitri Epshtein <dima@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>