drm/panthor: Add FOP_UNSIGNED_OFFSET to fop_flags

Since commit 641bb43 ("fs: move FMODE_UNSIGNED_OFFSET to fop_flags")
the FMODE_UNSIGNED_OFFSET flag has been moved to fop_flags and renamed,
but the patch failed to make the changes for the panthor driver.
When user space opens the render node the WARN() added by the patch
gets triggered.

Fixes: 641bb43 ("fs: move FMODE_UNSIGNED_OFFSET to fop_flags")
Cc: Christian Brauner <[email protected]>
Signed-off-by: Liviu Dudau <[email protected]>
Reviewed-by: Boris Brezillon <[email protected]>
Reviewed-by: Steven Price <[email protected]>
Reviewed-by: Christian Brauner <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Signed-off-by: Boris Brezillon <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: dliviu

drivers/gpu/drm/panthor/panthor_drv.c

@@ -1383,6 +1383,7 @@ static const struct file_operations panthor_drm_driver_fops = {
 	.read = drm_read,
 	.llseek = noop_llseek,
 	.mmap = panthor_mmap,
+	.fop_flags = FOP_UNSIGNED_OFFSET,
 };
 
 #ifdef CONFIG_DEBUG_FS