drm: bridge: fix unmet dependency on DRM_KMS_HELPER for DRM_PANEL_BRIDGE

When DRM_CHIPONE_ICN6211 is selected, and DRM_KMS_HELPER is not selected,
Kbuild gives the following warning:

WARNING: unmet direct dependencies detected for DRM_PANEL_BRIDGE
  Depends on [n]: HAS_IOMEM [=y] && DRM_BRIDGE [=y] && DRM_KMS_HELPER [=n]
  Selected by [y]:
  - DRM_CHIPONE_ICN6211 [=y] && HAS_IOMEM [=y] && DRM [=y] && DRM_BRIDGE [=y] && OF [=y]

This is because DRM_CHIPONE_ICN6211 selects DRM_PANEL_BRIDGE
without depending on or selecting DRM_KMS_HELPER,
despite DRM_PANEL_BRIDGE depending on DRM_KMS_HELPER.

This unmet dependency bug was detected by Kismet,
a static analysis tool for Kconfig.

Fixes: ce517f18

 ("drm: bridge: Add Chipone ICN6211 MIPI-DSI to RGB bridge")
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220117052146.75811-1-julianbraha@gmail.com