linux-yocto: Remove not supported targets

As long as some targets are not supported anymore, do not create
dtb and fit images:
- axm-ve-tc1 and axm-ve-tc2 were for the arm development boards, and are
  no longer used.
- We don't need both ACP344xV2 and acp344x.  V1 of the 3448 is no longer
  supported. Remove ACP344xV2 and use acp344x.

Signed-off-by: Daniel Dragomir <daniel.dragomir@windriver.com>