s390/spinlock: fix indentation

checkpatch:
    WARNING: Statements should start on a tabstop
    #9499: FILE: arch/s390/lib/spinlock.c:231:
    +                          return;

sparse:
arch/s390/lib/spinlock.c:81 arch_load_niai4()
    warn: inconsistent indenting
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

arch/s390/lib/spinlock.c

@@ -226,9 +226,10 @@ static inline void arch_spin_lock_classic(arch_spinlock_t *lp)
 		/* Try to get the lock if it is free. */
 		if (!owner) {
 			new = (old & _Q_TAIL_MASK) | lockval;
-			if (arch_cmpxchg_niai8(&lp->lock, old, new))
+			if (arch_cmpxchg_niai8(&lp->lock, old, new)) {
 				/* Got the lock */
 				return;
+			}
 			continue;
 		}
 		if (count-- >= 0)