drm/bridge: Select DRM_KMS_HELPER for DRM_PANEL_BRIDGE

Since the kconfig symbol of DRM_PANEL_BRIDGE is only adding
bridge/panel.o to drm_kms_helper object, we need to select
DRM_KMS_HELPER to make sure the file is actually getting built.

Otherwise with certain defconfigs e.g. devm_drm_of_get_bridge will not
be properly available:

  aarch64-linux-gnu-ld: drivers/phy/qualcomm/phy-qcom-qmp-combo.o: in function `qmp_combo_bridge_attach':
  drivers/phy/qualcomm/phy-qcom-qmp-combo.c:3204:(.text+0x8f4): undefined reference to `devm_drm_of_get_bridge'

Signed-off-by: Luca Weiss <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Neil Armstrong <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: lweiss-fairphone

drivers/gpu/drm/bridge/Kconfig

@@ -8,6 +8,7 @@ config DRM_BRIDGE
 config DRM_PANEL_BRIDGE
 	def_bool y
 	depends on DRM_BRIDGE
+	select DRM_KMS_HELPER
 	select DRM_PANEL
 	help
 	  DRM bridge wrapper of DRM panels