staging: panel: Fix single-open policy race condition

Fix the implementation of a single-open policy for both
devices (lcd and keypad) by using atomic_t instead of plain ints.

Signed-off-by: Mariusz Gorski <marius.gorski@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed