drm/panic: Do not select DRM_KMS_HELPER

DRM core code cannot call into DRM helper code, as this would lead to
circular references in the modular case.  Hence drop the selection of
DRM_KMS_HELPER.  It was unused anyway, as v10 switched from using
the DRM format helpers to its own color format conversion, cfr. commit
95443097 ("drm/panic: Add support for color format conversion").

Remove the unneeded include of <drm/drm_format_helper.h>.

Fixes: bf9fb17c ("drm/panic: Add a drm panic handler")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/60155f8c939ed286e324a7c12a1daa69fe49fcf6.1719391132.git.geert+renesas@glider.be

drivers/gpu/drm/Kconfig

@@ -108,7 +108,6 @@ config DRM_KMS_HELPER
 config DRM_PANIC
 	bool "Display a user-friendly message when a kernel panic occurs"
 	depends on DRM && !(FRAMEBUFFER_CONSOLE && VT_CONSOLE)
-	select DRM_KMS_HELPER
 	select FONT_SUPPORT
 	help
 	  Enable a drm panic handler, which will display a user-friendly message

drivers/gpu/drm/drm_panic.c

@@ -20,7 +20,6 @@
 #include <linux/types.h>
 
 #include <drm/drm_drv.h>
-#include <drm/drm_format_helper.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_modeset_helper_vtables.h>