drm/panel/raydium-rm692e5: select CONFIG_DRM_DISPLAY_DP_HELPER

As with several other panel drivers, this fails to link without the DP
helper library:

ld: drivers/gpu/drm/panel/panel-raydium-rm692e5.o: in function `rm692e5_prepare':
panel-raydium-rm692e5.c:(.text+0x11f4): undefined reference to `drm_dsc_pps_payload_pack'

Select the same symbols that the others already use.

Fixes: 988d0ff2 ("drm/panel: Add driver for BOE RM692E5 AMOLED panel")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231023115619.3551348-1-arnd@kernel.orgSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231023115619.3551348-1-arnd@kernel.org

drivers/gpu/drm/panel/Kconfig

@@ -530,6 +530,8 @@ config DRM_PANEL_RAYDIUM_RM692E5
 	depends on OF
 	depends on DRM_MIPI_DSI
 	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	help
 	  Say Y here if you want to enable support for Raydium RM692E5-based
 	  display panels, such as the one found in the Fairphone 5 smartphone.