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

This reverts commit de9bf1d8a2de952bfc17cdf7082b41f9c185e54d.

Change-Id: Iebb6297ce290a10ee850bf6a9c71e7eb530b085f
diff --git a/docs/plat/rpi3.rst b/docs/plat/rpi3.rst
index 5c7b6d5..38c3dfa 100644
--- a/docs/plat/rpi3.rst
+++ b/docs/plat/rpi3.rst
@@ -315,7 +315,7 @@
 
 .. code:: shell
 
-    CROSS_COMPILE=aarch64-none-elf- make PLAT=rpi3             \
+    CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi3             \
     RPI3_BL33_IN_AARCH32=1                                      \
     BL33=../rpi3-arm-tf-bootstrap/aarch32/el2-bootstrap.bin
 
@@ -323,7 +323,7 @@
 
 .. code:: shell
 
-    CROSS_COMPILE=aarch64-none-elf- make PLAT=rpi3             \
+    CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi3             \
     BL33=../rpi3-arm-tf-bootstrap/aarch64/el2-bootstrap.bin
 
 However, enabling PSCI support in a 64-bit kernel is really easy. In the
@@ -340,7 +340,7 @@
 
 .. code:: shell
 
-    CROSS_COMPILE=aarch64-none-elf- make PLAT=rpi3             \
+    CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi3             \
     PRELOADED_BL33_BASE=0x02000000                              \
     RPI3_PRELOADED_DTB_BASE=0x01000000                          \
     RPI3_DIRECT_LINUX_BOOT=1
@@ -349,7 +349,7 @@
 
 .. code:: shell
 
-    CROSS_COMPILE=aarch64-none-elf- make PLAT=rpi3             \
+    CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi3             \
     PRELOADED_BL33_BASE=0x02000000                              \
     RPI3_PRELOADED_DTB_BASE=0x01000000                          \
     RPI3_DIRECT_LINUX_BOOT=1                                    \