plugins: Expose physical addresses instead of device offsets

plugins: Expose physical addresses instead of device offsets

This allows plugins to query for full virtual-to-physical address
translation for a given `qemu_plugin_hwaddr` and stops exposing the
offset within the device itself. As this change breaks the API,
QEMU_PLUGIN_VERSION is incremented.

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210309202802.211756-1-aaron@os.amperecomputing.com>
Message-Id: <20210312172821.31647-3-alex.bennee@linaro.org>