Update Buildroot to version 2021.02

As Buildroot fixed [1] the glibc 2.33 compatibility issue, we should update
the Buildroot to reflect that change.

Link: [1] https://git.busybox.net/buildroot/commit/?id=f45925a951318e9e53bead80b363e004301adc6f
Signed-off-by: Mingyuan Xiang <xiang_my@outlook.com>
Acked-by: Jerome Forissier <jerome@forissier.org>
diff --git a/dra7xx.xml b/dra7xx.xml
index c0f492d..d90bec6 100644
--- a/dra7xx.xml
+++ b/dra7xx.xml
@@ -17,7 +17,7 @@
         <project path="optee_examples" name="linaro-swg/optee_examples.git" />
 
         <!-- Misc gits -->
-        <project path="buildroot"      name="buildroot/buildroot.git"             revision="refs/tags/2020.08" clone-depth="1" />
+        <project path="buildroot"      name="buildroot/buildroot.git"             revision="refs/tags/2021.02" clone-depth="1" />
         <project path="linux"          name="ti-linux-kernel/ti-linux-kernel.git" revision="00a3beacce33dc14fa301eb5f3fb5a341212e9b4" remote="ti" />
         <project path="u-boot"         name="ti-u-boot/ti-u-boot.git"             revision="c68ed086bd00054e28c46e033385f79104c3f84c" remote="ti" />
 </manifest>