uapi glibc compat: fix outer guard of net device flags enum

Fix a wrong condition preventing the higher net device flags
IFF_LOWER_UP etc to be defined if net/if.h is included before
linux/if.h.

The comment makes it clear the intention was to allow partial
definition with either parts.

This fixes compilation of userspace programs trying to use
IFF_LOWER_UP, IFF_DORMANT or IFF_ECHO.

Fixes: 4a91cb61 ("uapi glibc compat: fix compile errors when glibc net/if.h included before linux/if.h")
Signed-off-by: NJonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: NMikko Rapeli <mikko.rapeli@iki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/if.h

@@ -31,7 +31,7 @@
 #include <linux/hdlc/ioctl.h>
 
 /* For glibc compatibility. An empty enum does not compile. */
-#if __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 && \
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 || \
     __UAPI_DEF_IF_NET_DEVICE_FLAGS != 0
 /**
  * enum net_device_flags - &struct net_device flags
@@ -99,7 +99,7 @@ enum net_device_flags {
 	IFF_ECHO			= 1<<18, /* volatile */
 #endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
 };
-#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 && __UAPI_DEF_IF_NET_DEVICE_FLAGS != 0 */
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 || __UAPI_DEF_IF_NET_DEVICE_FLAGS != 0 */
 
 /* for compatibility with glibc net/if.h */
 #if __UAPI_DEF_IF_NET_DEVICE_FLAGS