PM / QoS: Set cpu_dma_pm_qos->name

Since commit 4a31a334, the name of this misc device is not initialized,
which leads to a funny device named /dev/(null) being created and
/proc/misc containing an entry with just a number but no name. The latter
leads to complaints by cryptsetup, which caused me to investigate this
matter.
Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

kernel/power/qos.c

@@ -70,6 +70,7 @@ static struct pm_qos_constraints cpu_dma_constraints = {
 };
 static struct pm_qos_object cpu_dma_pm_qos = {
 	.constraints = &cpu_dma_constraints,
+	.name = "cpu_dma_latency",
 };
 
 static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);