plat: marvell: armada: a3k: Split building $(WTMI_MULTI_IMG) and $(TIMDDRTOOL)

These two targets are build by make subprocesses and are independent.
So splitting them into own targets allow make to build them in parallel.
$(TIMBUILD) script depends on $(TIMDDRTOOL) so specify it in Makefile.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I139fc7fe64d8de275b01a853e15bfb88c4ff840d
1 file changed