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Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

libsel4vmmplatsupport: Update documentation

This commit refreshes the interface documentation in
libsel4vmmplatsupport. This commit patches in missing documentation
and additionally ensures all interface documentation conforms to
Doxygen style comments.

trivial: Style changed files

libsel4vmmplatsupport: device_utils use libsel4vm

Updated the device_utils to use libsel4vm for
registering device memory regions and fault handlers.
This is a general update to the device utils source to use
the updated interfaces in libsel4vm and libsel4vmmplatsupport.
Prior to this update device_utils would not compile/work.

libsel4vmmplatsupport: Moved device_utils header

Updated the location of the device_utils header such that its
include is namespaced under 'sel4vmmplatsupport'.