riscv: Map devices with large pages on 32 & 64-bit

For 64-bit, this adds a 2nd-level page table for mapping devices using
2MiB frames instead of 1GiB frames.

The boot mapping and hardware header generator have also been fixed to
correctly report the number of large frames needed for devices rather
than only reporting the first. The frame size is also specified
correctly (rather than assuming mapping with 4KiB frames).

This likely fixes an issue whereby only the first 4KiB frame of a device
was reserved but the remaining region of that kernel device could be
mapped at user level.

Signed-off-by: Curtis Millar <curtis.millar@data61.csiro.au>

tools: fix brackets in format parameters

Signed-off-by: Axel Heider <axelheider@gmx.de>

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.

tools: rewrite hardware_gen.py

This is almost a complete rewrite from the old hardware_gen.py.

It separates the 'parse DT' stage from the 'generate output'
devices more strictly, and is hopefully easier to understand and
easier to extend.

We also no longer generate the 'devices' list (in YAML)
or the dev_p_regs array (in C), as the kernel will implicitly
expose all non-RAM untypeds as devices.