arm-defaults: split out thumb, fixed when used with overrides
arm-defaults: split out thumb, fixed when used with overrides

meta-fsl-arm (yes, again) now uses overrides for DEFAULTTUNE which
messes up our magic. Sprinkle an override of our own in here to fix it.

Signed-off-by: Koen Kooi <42e3d96910f922bdd7dd1805fe3f8aff634f391d@dominion.thruhere.net>

Angstrom-distribution/meta-angstrom,Angstrom-distribution/meta-angstrom,Angstrom-distribution/meta-angstrom,Angstrom-distribution/meta-angstrom