At the time of writting, GCC 8.3-2019.03 is the latest version available
on developer.arm.com.

Switch to bare-metal toolchain (arm-eabi-) for AArch32. This allows to
have a finer control on the use of floating-point and SIMD instructions.

Change-Id: I4438401405eae1e5f6d531b0162e8fa06f69135e
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>