UAPI: Split trivial #if defined(__KERNEL__) && X conditionals

Split trivial #if defined(__KERNEL__) && X conditionals to make automated
disintegration easier.

Signed-off-by: David Howells <dhowells@redhat.com>

include/linux/mroute6.h

@@ -43,9 +43,11 @@ typedef unsigned short mifi_t;
 typedef	__u32		if_mask;
 #define NIFBITS (sizeof(if_mask) * 8)        /* bits per mask */
 
-#if !defined(__KERNEL__) && !defined(DIV_ROUND_UP)
+#if !defined(__KERNEL__)
+#if !defined(DIV_ROUND_UP)
 #define	DIV_ROUND_UP(x,y)	(((x) + ((y) - 1)) / (y))
 #endif
+#endif
 
 typedef struct if_set {
 	if_mask ifs_bits[DIV_ROUND_UP(IF_SETSIZE, NIFBITS)];