Update buildroot to 2020.08

Supports building with GCC 9.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Change-Id: Ieaa3a304ef3e414d0d067072d36e82a2eb2cc0e8
diff --git a/default.xml b/default.xml
index 55a70a7..cce7223 100644
--- a/default.xml
+++ b/default.xml
@@ -21,7 +21,7 @@
         <project path="soc_term"             name="linaro-swg/soc_term.git"               revision="5493a6e7c264536f5ca63fe7511e5eed991e4f20" />
 
         <!-- Misc gits -->
-        <project path="buildroot"            name="buildroot/buildroot.git"               revision="95942f5fcd35d783a49adce621ccf33480f1c88c" />
+        <project path="buildroot"            name="buildroot/buildroot.git"               revision="refs/tags/2020.08" clone-depth="1" />
         <project path="qemu"                 name="qemu/qemu.git"                         revision="refs/tags/v5.1.0" clone-depth="1" />
         <project path="trusted-firmware-a"   name="TF-A/trusted-firmware-a.git"           revision="refs/tags/v2.3" remote="tfo" />
         <project path="u-boot"               name="u-boot.git"                            revision="refs/tags/v2020.04" remote="u-boot" clone-depth="1" />