Implement a SyncReadMem wrapper with explicit read, write, and read/write...

Implement a SyncReadMem wrapper with explicit read, write, and read/write ports (backport #3228) (#3361)

* Implement a SyncReadMem wrapper with explicit read, write, and readwrite ports (#3228)

Co-authored-by: Jiuyang Liu <liu@jiuyang.me>
Co-authored-by: Jack Koenig <koenig@sifive.com>
(cherry picked from commit 8851faed

)

* Delete typeName def

---------

Co-authored-by: Jared Barocsi <82000041+jared-barocsi@users.noreply.github.com>
Co-authored-by: Jared Barocsi <jared.barocsi@sifive.com>