misc: k3_avs: Fix possible NULL pointer deference

Its possible that k3_avs_priv is NULL because the driver may not have
been probed yet. Therefore check if pointer is valid before
dereferencing it.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
diff --git a/drivers/misc/k3_avs.c b/drivers/misc/k3_avs.c
index 47e4273..90df377 100644
--- a/drivers/misc/k3_avs.c
+++ b/drivers/misc/k3_avs.c
@@ -191,6 +191,10 @@
 	struct k3_avs_privdata *priv = k3_avs_priv;
 	struct vd_data *vd;
 
+	/* Driver may not be probed yet */
+	if (!priv)
+		return -EINVAL;
+
 	for (vd = priv->vd_config->vds; vd->id >= 0; vd++) {
 		if (vd->dev_id != dev_id || vd->clk_id != clk_id)
 			continue;