staging: most: use unsafe version of list traversing

The function get_net_dev_context does not remove elements of the list.
Hence, list traversing does not need to be secured.

This patch replaces list_for_each_entry_safe with the
list_for_each_entry.

Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>