[MIPS] Reformat __xchg().

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/system.h

@@ -286,10 +286,10 @@ extern void __xchg_called_with_bad_pointer(void);
 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 {
 	switch (size) {
-		case 4:
-			return __xchg_u32(ptr, x);
-		case 8:
-			return __xchg_u64(ptr, x);
+	case 4:
+		return __xchg_u32(ptr, x);
+	case 8:
+		return __xchg_u64(ptr, x);
 	}
 	__xchg_called_with_bad_pointer();
 	return x;