plugins: Add memory virtual address write API

plugins: Add memory virtual address write API

This patch adds functions to the plugins API to allow reading and
writing memory via virtual addresses. These functions only permit doing
so on the current CPU, because there is no way to ensure consistency if
plugins are allowed to read or write to other CPUs that aren't currently
in the context of the plugin.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Rowan Hart <rowanbhart@gmail.com>
Message-ID: <20250624175351.440780-5-rowanbhart@gmail.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-ID: <20250627112512.1880708-9-alex.bennee@linaro.org>