Interface: Split os_wrapper to multiple headers

To enable the ability to optionally install the os_wrapper headers for
different build configurations and make the os_wrapper more clear in
the file structure.
This patch splits the os_wrapper.h to multiple files by modules.

Change-Id: I48ad677f745fdee20a5a9b5e366e862d7b7dc58e
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
8 files changed