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>

plat: imx8m: Add the basic support for imx8mm ...

The i.MX8M Mini is new SOC of the i.MX8M family. it is
focused on delivering the latest and greatest video and
audio experience combining state-of-the-art media-specific
features with high-performance processing while optimized
for lowest power consumption. The i.MX 8M Mini Media Applications
Processor is  14nm FinFET product of the growing i.MX8M family
targeting the consumer & industrial market. It is built in 14LPP
to achieve both high performance and low power consumption
and relies on a powerful fully coherent core complex based on
a quad Cortex-A53 cluster with video and graphics accelerators

this patch add the basic support for i.MX8MM.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>

plat: imx: Add i.MX8MQ basic support ...

i.MX8MQ is new SOC of NXP's i.MX8M family based on
A53. It can provide industry-leading audio, voice
and video processing for applications that scale
from consumer home audio to industrial building
automation and mobile computers

this patchset add the basic supoort to boot up
the 4 X A53. more feature will be added later.

Signed-off-by: Bai Ping <ping.bai@nxp.com>