spi: mpc52xx: Add cancel_work_sync before module remove

spi: mpc52xx: Add cancel_work_sync before module remove

If we remove the module which will call mpc52xx_spi_remove
it will free 'ms' through spi_unregister_controller.
while the work ms->work will be used. The sequence of operations
that may lead to a UAF bug.

Fix it by ensuring that the work is canceled before proceeding with
the cleanup in mpc52xx_spi_remove.

Fixes: ca632f556697 ("spi: reorganize drivers")
Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Link: https://patch.msgid.link/1f16f8ae0e50ca9adb1dc849bf2ac65a40c9ceb9.1732783000.git.xiaopei01@kylinos.cn
Signed-off-by: Mark Brown <broonie@kernel.org>