RPi2 Proposal to change the memory map

[Chris Johns]

Hello,

Sebastian from Embedded Brains has kindly posted a patch to the development list
that adds a welcome feature present on other ARM boards, NULL pointer access
checking. An access to a NULL pointer will generate an exception so you know if
your application is referencing a NULL pointer.

The patch is here ..

https://lists.rtems.org/pipermail/devel/2019-July/026923.html

The thread related to this patch can be viewed here ..

https://lists.rtems.org/pipermail/devel/2019-July/026908.html

The v3 patch requires all user change their `mkimage` command as the memory map
will change. I will update the rtems-boot-image tool to support the raspberrypi2
and this new mamory map.

Comments?

Thanks
Chris