module: Use strscpy() for last_unloaded_module

The use of strlcpy() is considered deprecated [1].
In this particular context, there is no need to remain with strlcpy().
Therefore we transition to strscpy().

[1]: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy



Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>