drivers: dma: max32: check if bit other than status is set

we iterate over all the channels, and if more than one channel is
active at a time. interrupt on any one of active channel was
triggering callback for other active channel, because flags value
is 1 (enabled). this is commit handle this behaviour and only
trigger callback if bits other than status is set

Signed-off-by: Anuj Pathak <anuj@croxel.com>