[PATCH] drm/panthor: Set FMODE_UNSIGNED_OFFSET in fop_flags

[Emmanuel Gil Peyrot <linkmauve@xxxxxxxxxxxx>]

This fixes a regression introduced in commit
641bb4394f405cba498b100b44541ffc0aed5be1.  No panthor device, card or
render node, could be open() since this commit, returning EINVAL
instead.  This prevented Mesa from working on SoCs such as the rk3588
which contains a Mali-G610 GPU.

The commit mentions which drivers must be changed to set that flag, but
panthor seemingly got forgotten, triggering the WARN_ON_ONCE() added
in drm_open_helper().
---
 drivers/gpu/drm/panthor/panthor_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 34182f67136c..c520f156e2d7 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/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
-- 
2.46.2