[OE-core] gcc-cross-canadian-i586 doesn't work PREFERRED_VERSION

[Robert Yang]

Currently in oe-core, the default GCCVERSION is 4.9, and we also have
gcc 5.1, so when:

MACHINE = "qemux86-64"
require conf/multilib.conf
MULTILIBS = "multilib:lib32"
DEFAULTTUNE_virtclass-multilib-lib32 = "x86"


$ bitbake gcc-cross-canadian-i586

Then the 5.1 has been built, though we had set 4.9 in tcmode-default.inc:

PREFERRED_VERSION_gcc-cross-canadian-${TRANSLATED_TARGET_ARCH} ?= "${GCCVERSION}"

The funny is that if we build gcc-cross-i586, then 4.9 would be built,
Any ideas on how to fix it, please ?

-- 
Thanks

Robert