graphics/libyuv: Download libyuv from NuttX Mirror Repo

NuttX Build Target `sim:nxcamera` failed to build because chromium.googlesource.com is blocking our download of libyuv library: https://github.com/apache/nuttx/actions/runs/24106742084/job/70356374433#step:10:603

```
Configuration/Tool: sim/nxcamera
Building NuttX...
curl -L https://chromium.googlesource.com/libyuv/libyuv/+archive/refs/heads/stable.tar.gz -o libyuv.tar.gz
gzip: stdin: not in gzip format
```

This PR updates the libyuv Makefile to download libyuv from the NuttX Mirror Repo instead: https://github.com/NuttX/nuttx/releases/tag/libyuv

Signed-off-by: Lup Yuen Lee <luppy@appkaki.com>

Author: lupyuen

graphics/libyuv/Makefile

@@ -29,7 +29,7 @@ CXXFLAGS += -Wno-shadow -Wno-undef
 CXXSRCS = $(wildcard $(SRCDIR)/source/*.cc)
 
 libyuv.tar.gz:
-	$(Q) curl -L https://chromium.googlesource.com/libyuv/libyuv/+archive/refs/heads/$(CONFIG_LIBYUV_BRANCH).tar.gz -o libyuv.tar.gz
+	$(Q) curl -L https://github.com/NuttX/nuttx/releases/download/libyuv/libyuv-refs_heads_$(CONFIG_LIBYUV_BRANCH).tar.gz -o libyuv.tar.gz
 	$(Q) mkdir -p $(SRCDIR)
 	$(Q) tar zxf libyuv.tar.gz --directory $(SRCDIR)
 ifeq ($(CONFIG_LIBYUV_BRANCH),"stable")