optee-test_3.2.0.imx: fix TA_DEV_KIT_DIR is not correctly defined error
DEFAULTTUNE is no longer aarch64 which means optee-test
build fails. Update to use the same mechanism as optee-os
recipe for setting arch.
Build now passes on imx8mq-evk and optee xtest suite
passes
+-----------------------------------------------------
16078 subtests of which 3 failed
74 test cases of which 3 failed
0 test case was skipped
TEE test application done!
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
