Put -lfirmware in CORE_LIBS, to fix -thumb builds

For unknown reasons, -thumb builds need -lfirmware after -lrbcodec (but
still before -lunwarminder)i. Other builds are still happy if we do that.
Including it via CORE_LIBS instead of explicitly achieves that.

Change-Id: Id69e4a0c042f90f71cfd9a72202ce4d8ef6a4181
2 files changed