drm/fbdev: Select FB_CORE dependency for fbdev on DMA and TTM

Select FB_CORE if GEM's DMA and TTM implementations support fbdev
emulation. Fixes linker errors about missing symbols from the fbdev
subsystem.

Also see [1] for a related SHMEM fix.

Fixes: dadd28d ("drm/client: Add client-lib module")
Signed-off-by: Thomas Zimmermann <[email protected]>
Link: https://patchwork.freedesktop.org/series/141411/ # 1
Reviewed-by: Arnd Bergmann <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Thomas Zimmermann

drivers/gpu/drm/Kconfig

@@ -358,13 +358,15 @@ config DRM_TTM_HELPER
 	tristate
 	depends on DRM
 	select DRM_TTM
+	select FB_CORE if DRM_FBDEV_EMULATION
 	select FB_SYSMEM_HELPERS_DEFERRED if DRM_FBDEV_EMULATION
 	help
 	  Helpers for ttm-based gem objects
 
 config DRM_GEM_DMA_HELPER
 	tristate
 	depends on DRM
+	select FB_CORE if DRM_FBDEV_EMULATION
 	select FB_DMAMEM_HELPERS_DEFERRED if DRM_FBDEV_EMULATION
 	help
 	  Choose this if you need the GEM DMA helper functions