bfin: change default to bf532, internal toolchain !bf6xx
The default Blackfin processor in Buildroot isn't supported by
gcc 6.1.0, so use bf532 as default. Disable any bf6xx processors
for internal toolchain users.
Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>