doc: Reformat platform port documents ...

The platform port documents are not very standardised right now and
they don't integrate properly into the document tree so:

1) Make sure each port has a proper name and title (incl. owner)
2) Correct use of headings, subheadings, etc in each port
3) Resolve any naming conflicts between documents

Change-Id: I4c2da6f57172b7f2af3512e766ae9ce3b840b50f
Signed-off-by: Paul Beesley <paul.beesley@arm.com>

Initialize platform for MediaTek mt8183 ...

- Add basic platform setup
- Add generic CPU helper functions
- Add delay timer platform implementation
- Use TI 16550 uart driver

Change-Id: I1c29569c68fe9fca5e10e88a22a29690bab7141f
Signed-off-by: kenny liang <kenny.liang@mediatek.com>