Convert license tags to SPDX identifiers

This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.

style: consistently align pointer with name

Run astyle with align-pointer=name

s/DEBUG/CONFIG_DEBUG_BUILD/

DEBUG definition is not supposed to be used in the kernel, rather CONFIG_DEBUG_BUILD,
which can be toggled separately to user notion of DEBUG

Release snapshot