staging: most: remove exclusive wait_queue

This patch removes the unnecessary wait_queue that has exclusively been
used for the poll function and its poll_table. Instead, an already
existing one is used.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>