ARM: 5675/1: The semaphore is used as mutex so make it a mutex

The semaphore is used as mutex so make it a mutex.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>