[PATCH wpan] net: ieee802154: handle iftypes as u32

This patch fixes an issue that an u32 netlink value is handled as a
signed enum value which doesn't fit into the range of u32 netlink type.
If it's handled as -1 value some BIT() evaluation ends in a
shift-out-of-bounds issue. To solve the issue we set the to u32 max which
is s32 "-1" value to keep backwards compatibility and let the followed enum
values start counting at 0. This brings the compiler to never handle the
enum as signed and a check if the value is above NL802154_IFTYPE_MAX should
filter -1 out.

Fixes: f3ea5e44231a ("ieee802154: add new interface command")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
  include/net/nl802154.h | 7 ++++---
  1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/net/nl802154.h b/include/net/nl802154.h
index ddcee128f5d9..145acb8f2509 100644
--- a/include/net/nl802154.h
+++ b/include/net/nl802154.h

@@ -19,6 +19,8 @@
   *
   */
  
+#include <linux/types.h>
+
  #define NL802154_GENL_NAME "nl802154"
  
  enum nl802154_commands {

@@ -150,10 +152,9 @@ enum nl802154_attrs {
  };
  
  enum nl802154_iftype {
-	/* for backwards compatibility TODO */
-	NL802154_IFTYPE_UNSPEC = -1,
+	NL802154_IFTYPE_UNSPEC = (~(__u32)0),
  
-	NL802154_IFTYPE_NODE,
+	NL802154_IFTYPE_NODE = 0,
  	NL802154_IFTYPE_MONITOR,
  	NL802154_IFTYPE_COORD,