Convert to SPDX license tags

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

trivial: Style changed files

libsel4vmmplatsupport: arch include -> arch subdir

Moved the architecture specific headers, being unique header files
that only exist for a given architecture, into an 'arch'
subdirectory. Since this library can be used across architectures
this avoids polluting the root libsel4vmmplatsupport namespace and
adds further structure to distinguish different interfaces.

libsel4vm: Moved device drivers to vmmplatsupport

Moved the arm device drivers from libsel4vm out to
libsel4vmmplatsupport.These are optional devices a VMM may choose
to initialise and hence do not need to be managed by libsel4vm.
Note these devices do NOT compile and need to be updated to use
the new memory interface for reservation management and
fault handling. This is an intermediate commit in preperation for
updating the device drivers.