mem: splitting dram and nvm interfaces into separate files

This change primarily splits the dram and nvm interfaces
into separate files. And also updates the interfaces so that
they can be handled in a more general way by the controller.
For example, both interfaces now override a virtual isBusy()
function defined in the mem_interface.

Change-Id: Id98bf0be3836a4b6245d5dea1b8fad0a60ce299a
Reviewed-by: Jason Lowe-Power <>
Tested-by: kokoro <>
Maintainer: Jason Lowe-Power <>
Maintainer: Bobby Bruce <>
Reviewed-by: Bobby Bruce <>
11 files changed