staging: unisys: visorinput: remove unnecessary locking

staging: unisys: visorinput: remove unnecessary locking

Locking in the _interrupt() function is NOT necessary so long as we ensure
that interrupts have been stopped whenever we need to pause or resume the
device, which we now do.

While a device is paused, we ensure that interrupts stay disabled, i.e.
that the _interrupt() function will NOT be called, yet remember the desired
state in devdata->interrupts_enabled if open() or close() are called are
called while the device is paused.  Then when the device is resumed, we
restore the actual state of interrupts (i.e., whether _interrupt() is going
to be called or not) to the desired state in devdata->interrupts_enabled.

Signed-off-by: Tim Sell <Timothy.Sell@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Acked-By: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>