UPSTREAM: drm/tegra: Count number of display controllers at runtime

In order to be able to attach planes to all possible display controllers
the exact number of CRTCs must be known. Keep track of the number of the
display controllers that register during initialization.

Change-Id: I06d2afdbe23bb3865f5ca4c8e7d1dbbc9f09ac43
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2545944
Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/gpu/drm/tegra/drm.h

@@ -55,6 +55,7 @@ struct tegra_drm {
 
 	unsigned int hmask, vmask;
 	unsigned int pitch_align;
+	unsigned int num_crtcs;
 
 	struct tegra_display_hub *hub;
 };