Revert "GCC: Upgrade to version 9.2-2019.12 of toolchain"

This reverts commit de9bf1d8a2de952bfc17cdf7082b41f9c185e54d.

Change-Id: Iebb6297ce290a10ee850bf6a9c71e7eb530b085f
diff --git a/docs/plat/qemu-sbsa.rst b/docs/plat/qemu-sbsa.rst
index 5e8535c..51fe414 100644
--- a/docs/plat/qemu-sbsa.rst
+++ b/docs/plat/qemu-sbsa.rst
@@ -27,7 +27,7 @@
 
     git clone https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git tfa
     cd tfa
-    export CROSS_COMPILE=aarch64-none-elf-
+    export CROSS_COMPILE=aarch64-linux-gnu-
     make PLAT=qemu_sbsa all fip
 
 Images will be placed at build/qemu_sbsa/release (bl1.bin and fip.bin).