IVGCVSW-2758 Instructions for cross-compiling ArmNN for arm64 should install cross-compiling toolchain earlier
IVGCVSW-2758 Instructions for cross-compiling ArmNN for arm64 should install cross-compiling toolchain earlier

Change-Id: I4c64eea6fa17cd4b1c817d4bf8337ebce75851dd
Signed-off-by: Ruomei Yan <65b2bd8a2d760c0c797144457ced8a8893aa277d@arm.com>

ARM-software/armnn,ARM-software/armnn,ARM-software/armnn