drm/bridge: ptn3460: Fix sparse warnings
drm/bridge: ptn3460: Fix sparse warnings

The ptn3460_bridge_attach symbol is never used outside this file, so it
should be static.

Signed-off-by: Thierry Reding <3055038c414aef68bf32c33b8118623e7554e0f2@nvidia.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs