Reserve space in super for dynamic partition metadata

The maximum size of all dynamic partition groups should not exceed
the super size - DAP metadata size. Today the configuration of
the device doesn't take the metadata into acount.

Since we recommend 4M to partners, reserve 4M here.

Bug: 182431975
Test: build
Change-Id: I648017e4737a96d663449b8b27f1c6c19730e6cd
1 file changed