s390/rwlock: add missing local_irq_restore calls

The out of line _raw_read_lock_wait_flags/_raw_write_lock_wait_flags
functions for the arch_read_lock_flags/arch_write_lock_flags  calls
fail to re-enable the interrupts after another unsuccessful try to
get the lock with compare-and-swap. The following wait would be
done with interrupts disabled which is suboptimal.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/lib/spinlock.c

@@ -143,6 +143,7 @@ void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
 		local_irq_disable();
 		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
 			return;
+		local_irq_restore(flags);
 	}
 }
 EXPORT_SYMBOL(_raw_read_lock_wait_flags);
@@ -199,6 +200,7 @@ void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags)
 		local_irq_disable();
 		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
 			return;
+		local_irq_restore(flags);
 	}
 }
 EXPORT_SYMBOL(_raw_write_lock_wait_flags);