Documentation: gpu/drm-uapi: eliminate duplicated word

Drop the doubled word "when".
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Link: https://lore.kernel.org/r/20200707180414.10467-8-rdunlap@infradead.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/gpu/drm-uapi.rst

@@ -195,7 +195,7 @@ ENOSPC:
 EPERM/EACCES:
         Returned for an operation that is valid, but needs more privileges.
         E.g. root-only or much more common, DRM master-only operations return
-        this when when called by unpriviledged clients. There's no clear
+        this when called by unpriviledged clients. There's no clear
         difference between EACCES and EPERM.
 
 ENODEV: