drm/fbdev: rework output polling to be back in the core. (v4)

After thinking it over a lot it made more sense for the core to deal with
the output polling especially so it can notify X.

v2: drop plans for fake connector - per Michel's comments - fix X patch sent to xorg-devel, add intel polled/hpd setting, add initial nouveau polled/hpd settings.

v3: add config lock take inside polling, add intel/nouveau poll init/fini calls

v4: config lock was a bit agressive, only needed around connector list reading.
otherwise it could re-enter.

glisse: discard drm_helper_hpd_irq_event

v3: Reviewed-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index be5aa7d..2583ddf 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -9,6 +9,7 @@
 	depends on (AGP || AGP=n) && PCI && !EMULATED_CMPXCHG && MMU
 	select I2C
 	select I2C_ALGOBIT
+	select SLOW_WORK
 	help
 	  Kernel-level support for the Direct Rendering Infrastructure (DRI)
 	  introduced in XFree86 4.0. If you say Y here, you need to select
@@ -23,7 +24,6 @@
 	depends on DRM
 	select FB
 	select FRAMEBUFFER_CONSOLE if !EMBEDDED
-	select SLOW_WORK
 	help
 	  FB and CRTC helpers for KMS drivers.