s5p-mfc: Set device name for reserved memory region devs

The devices don't have a name set, so makes dev_name() returns NULL which
makes harder to identify the devices that are causing issues, for example:

WARNING: CPU: 2 PID: 616 at drivers/base/core.c:251 device_release+0x8c/0x90
Device '(null)' does not have a release() function, it is broken and must be fixed.

And after setting the device name:

WARNING: CPU: 0 PID: 591 at drivers/base/core.c:251 device_release+0x8c/0x90
Device 's5p-mfc-l' does not have a release() function, it is broken and must be fixed.

Cc: <stable@vger.kernel.org>
Fixes: 6e83e6e2 ("[media] s5p-mfc: Fix kernel warning on memory init")
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

drivers/media/platform/s5p-mfc/s5p_mfc.c

@@ -1062,6 +1062,8 @@ static int s5p_mfc_alloc_memdevs(struct s5p_mfc_dev *dev)
 		mfc_err("Not enough memory\n");
 		return -ENOMEM;
 	}
+
+	dev_set_name(dev->mem_dev_l, "%s", "s5p-mfc-l");
 	device_initialize(dev->mem_dev_l);
 	of_property_read_u32_array(dev->plat_dev->dev.of_node,
 			"samsung,mfc-l", mem_info, 2);
@@ -1079,6 +1081,8 @@ static int s5p_mfc_alloc_memdevs(struct s5p_mfc_dev *dev)
 		mfc_err("Not enough memory\n");
 		return -ENOMEM;
 	}
+
+	dev_set_name(dev->mem_dev_r, "%s", "s5p-mfc-r");
 	device_initialize(dev->mem_dev_r);
 	of_property_read_u32_array(dev->plat_dev->dev.of_node,
 			"samsung,mfc-r", mem_info, 2);