rust: Improve TUNE_FEATURE parsing
rust: Improve TUNE_FEATURE parsing

Since https://github.com/openembedded/openembedded-core/commit/ac83d22eb5031f7fdd09d34a1a46d92fd3e39a3c

The armvX arch definition is not present in TUNE_FEATURES but is now in
MACHINEOVERRIDES. Improve parsing so that MACHINEOVERRIDES is also checked.

Fixes #240

Tested on raspberrypi3 with balenaOS which uses rust.

Signed-off-by: Zubair Lutfullah Kakakhel <0e069c2b28e50c7879834cb1889890ac34260249@balena.io>

meta-rust/meta-rust,meta-rust/meta-rust,meta-rust/meta-rust,meta-rust/meta-rust,meta-rust/meta-rust