vfio/fsl-mc: fix the return of the uninitialized variable ret

The vfio_fsl_mc_reflck_attach function may return, on success path,
an uninitialized variable. Fix the problem by initializing the return
variable to 0.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: f2ba7e8c94 ("vfio/fsl-mc: Added lock support in preparation for interrupt handling")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/fsl-mc/vfio_fsl_mc.c

@@ -58,7 +58,7 @@ static struct vfio_fsl_mc_reflck *vfio_fsl_mc_reflck_alloc(void)
 
 static int vfio_fsl_mc_reflck_attach(struct vfio_fsl_mc_device *vdev)
 {
-	int ret;
+	int ret = 0;
 
 	mutex_lock(&reflck_lock);
 	if (is_fsl_mc_bus_dprc(vdev->mc_dev)) {