Staging: Use proper mutexes in the tsi-148 VME driver

The VME core and tsi-148 driver currently use semaphores as mutexes. Switch to proper
mutex implementation.

Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>