drm: Silence sparse warnings

../drivers/gpu/drm/drm_vm.c:405:6: warning: symbol 'drm_vm_open_locked' was not declared. Should it be static?
../drivers/gpu/drm/drm_vm.c:431:6: warning: symbol 'drm_vm_close_locked' was not declared. Should it be static?
../drivers/gpu/drm/drm_vm.c:681:5: warning: symbol 'drm_vma_info' was not declared. Should it be static?

../drivers/gpu/drm/drm_pci.c:146:5: warning: symbol 'drm_pci_set_unique' was not declared. Should it be static?
../drivers/gpu/drm/drm_pci.c:216:5: warning: symbol 'drm_irq_by_busid' was not declared. Should it be static?

../drivers/gpu/drm/drm_info.c:47:5: warning: symbol 'drm_name_info' was not declared. Should it be static?
../drivers/gpu/drm/drm_info.c:72:5: warning: symbol 'drm_vm_info' was not declared. Should it be static?
../drivers/gpu/drm/drm_info.c:116:5: warning: symbol 'drm_bufs_info' was not declared. Should it be static?
../drivers/gpu/drm/drm_info.c:159:5: warning: symbol 'drm_clients_info' was not declared. Should it be static?
../drivers/gpu/drm/drm_info.c:209:5: warning: symbol 'drm_gem_name_info' was not declared. Should it be static?

../drivers/gpu/drm/drm_ioc32.c:1019:20: warning: symbol 'drm_compat_ioctls' was not declared. Should it be static?

../drivers/gpu/drm/drm_bridge.c:52:12: warning: function 'drm_bridge_attach' with external linkage has definition

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>