staging: most: block module removal while having active configfs items

This patch avoids that core component modules are being unloaded
while the related configfs interface has active items in its directories.
It is needed to prevent the situation where the core module cannot
be unloaded anymore, because the reference count 'used by' indicates that
the module is still being used and the usage count cannot be decreased by
calling rmdir, as the configfs directory has already been removed.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Link: https://lore.kernel.org/r/1573230068-27658-3-git-send-email-christian.gromm@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>