UniCore32-bugfix: fix mismatch return value of __xchg_bad_pointer

commit 195d4577d1d7ab1f0398b3190547c116b56f435f upstream.

When disintegrate system.h, I left an error in asm/cmpxchg.h, which
will result in following error:

arch/unicore32/include/asm/cmpxchg.h: In function '__xchg':
arch/unicore32/include/asm/cmpxchg.h:38: error: void value not ignored as it ought to be

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
diff --git a/arch/unicore32/include/asm/cmpxchg.h b/arch/unicore32/include/asm/cmpxchg.h
index df4d5ac..8e797ad 100644
--- a/arch/unicore32/include/asm/cmpxchg.h
+++ b/arch/unicore32/include/asm/cmpxchg.h
@@ -35,7 +35,7 @@
 			: "memory", "cc");
 		break;
 	default:
-		ret = __xchg_bad_pointer();
+		__xchg_bad_pointer();
 	}
 
 	return ret;