anlogic: implement DRAM initialization

anlogic: implement DRAM initialization

As the TD tool doesn't accept the DRAM cell to contain unknown values in
the initial value, the initialzation support of DRAM is previously
skipped.

Now add the support by add a new pass to determine unknown values in the
initial value.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>