arc: use swap() to make code cleaner

Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.
Signed-off-by: Yihao Han <hanyihao@vivo.com>
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>

arch/arc/kernel/unwind.c

@@ -245,14 +245,9 @@ static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
 {
 	struct eh_frame_hdr_table_entry *e1 = p1;
 	struct eh_frame_hdr_table_entry *e2 = p2;
-	unsigned long v;
-
-	v = e1->start;
-	e1->start = e2->start;
-	e2->start = v;
-	v = e1->fde;
-	e1->fde = e2->fde;
-	e2->fde = v;
+
+	swap(e1->start, e2->start);
+	swap(e1->fde, e2->fde);
 }
 
 static void init_unwind_hdr(struct unwind_table *table,