drivers/virt/fsl_hypervisor: remove unneeded `ret` variable in `fsl_hv_open()`

Fix the following coccicheck warning:

drivers/virt/fsl_hypervisor.c:662:5-8: Unneeded variable: "ret".
Return "0" on line 679.

Signed-off-by: Guo Zhengkui <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/virt/fsl_hypervisor.c

···
 {
 	struct doorbell_queue *dbq;
 	unsigned long flags;
-	int ret = 0;
 
 	dbq = kzalloc(sizeof(struct doorbell_queue), GFP_KERNEL);
 	if (!dbq) {
···
 
 	filp->private_data = dbq;
 
-	return ret;
+	return 0;
 }
 
 /*