Add kernel 5.15 for RPI4 support

root/target/linux/bcm27xx/patches-5.15/0190-drm-v3d-Plug-dma_fence-leak.patch

@@ -0,0 +1,33 @@
+From 221c9ee03ed568457aa2b32054157b654ef4be87 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Tue, 12 Nov 2019 16:41:21 +0000
+Subject: [PATCH 190/634] drm/v3d: Plug dma_fence leak
+
+The irq_fence and done_fence are given a reference that is never
+released. The necessary dma_fence_put()s seem to have been
+deleted in error in an earlier commit.
+
+Fixes: 0b73676836b2 ("drm/v3d: Clock V3D down when not in use.")
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/gpu/drm/v3d/v3d_gem.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
+index 7ca97c3d7975..a378a0cc67c2 100644
+--- a/drivers/gpu/drm/v3d/v3d_gem.c
++++ b/drivers/gpu/drm/v3d/v3d_gem.c
+@@ -414,6 +414,9 @@ v3d_job_free(struct kref *ref)
+ 	}
+ 	xa_destroy(&job->deps);
+ 
++	dma_fence_put(job->irq_fence);
++	dma_fence_put(job->done_fence);
++
+ 	v3d_clock_up_put(v3d);
+ 
+ 	if (job->perfmon)
+-- 
+2.33.1
+