Convert to SPDX license tags

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

libsel4vm*: Switch malloc calls to calloc

Reduces chances of an uninitialised structure being used and causing
issues that are painful to debug.

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.

libsel4vmmplatsupport: Updated licence years

Updated the year in the license headers.

libsel4vmmplatsupport: Removed debug print defines

Replaced custom debug print defines with ZF_LOGD.

libsel4vmmplatsupport: plat devices use libsel4vm

Updated the plat device drivers to use libsel4vm for
registering their device memory regions and their fault handlers.
This is a general update to the platform devices to use
the updated interfaces in libsel4vm and libsel4vmmplatsupport.
Prior to this update the devices would not compile/work.

sel4vmmplatsupport: Moved plat devices from sel4vm

Added an initial library 'sel4vmmplatsupport' to contain platform
specific drivers and utilities. This is introduced now to hold
the various arm platform devices. This library DOES NOT currently
compile. The code moved needs to be re-evaluated and updated to
to use a new memory interface and device registration interface.