staging: r8712u: Simplify semaphores

I am preparing to convert this driver from semaphore to mutex locking,
The first step has been to eliminate a number of semaphores that were
initialized but never used, and one whose only use was a single "up"
after initialization. A total of 9 semaphores were removed in this process.

One other change was to remove some inline semaphore routines that were
unused.

In addition, several cases had the following structure:

down()
if () {
   ...
}
up()

The locking overhead was reduced by moving the up/down inside the if
block.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>