net: mvpp2: fix interrupt mask/unmask skip condition

[ Upstream commit 7867299c ]

The condition should be skipped if CPU ID equal to nthreads.
The patch doesn't fix any actual issue since
nthreads = min_t(unsigned int, num_present_cpus(), MVPP2_MAX_THREADS).
On all current Armada platforms, the number of CPU's is
less than MVPP2_MAX_THREADS.

Fixes: e531f767

 ("net: mvpp2: handle cases where more CPUs are available than s/w threads")
Reported-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Stefan Chulski <stefanc@marvell.com>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>