pcmcia/vrc4171: Add missing spinlock init

commit 811af9723859884f2f771f3174f3ddedab7c53b5 upstream.

It doesn't seem this spinlock was properly initialized. This bug was
introduced by commit 7a410e8d4d97457c8c381e2de9cdc7bd3306badc.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>