arm: k3: Use driver_name to get ti_sci handle

Use the driver name to get ti_sci handle rather than relying
on just the FIRMWARE uclass.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
index 97aa15d..f8274b3 100644
--- a/arch/arm/mach-k3/common.c
+++ b/arch/arm/mach-k3/common.c
@@ -22,7 +22,8 @@
 	struct udevice *dev;
 	int ret;
 
-	ret = uclass_get_device(UCLASS_FIRMWARE, 0, &dev);
+	ret = uclass_get_device_by_driver(UCLASS_FIRMWARE,
+					  DM_GET_DRIVER(ti_sci), &dev);
 	if (ret)
 		panic("Failed to get SYSFW (%d)\n", ret);