netlink: specs: ethtool: define header-flags as an enum

Recent changes added header flags to the spec.
Use an enum instead of defines for more seamless codegen.

[Jakub: drop the already applied parts and rewrite message]
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Link: https://lore.kernel.org/r/20240403212931.128541-6-rrameshbabu@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/ethtool.yaml

@@ -18,7 +18,6 @@ definitions:
     entries: []
   -
     name: header-flags
-    enum-name:
     type: flags
     entries: [ compact-bitsets, omit-reply, stats ]
 

include/uapi/linux/ethtool_netlink.h

@@ -117,12 +117,11 @@ enum {
 
 /* request header */
 
-/* use compact bitsets in reply */
-#define ETHTOOL_FLAG_COMPACT_BITSETS	(1 << 0)
-/* provide optional reply for SET or ACT requests */
-#define ETHTOOL_FLAG_OMIT_REPLY	(1 << 1)
-/* request statistics, if supported by the driver */
-#define ETHTOOL_FLAG_STATS		(1 << 2)
+enum ethtool_header_flags {
+	ETHTOOL_FLAG_COMPACT_BITSETS	= 1 << 0,	/* use compact bitsets in reply */
+	ETHTOOL_FLAG_OMIT_REPLY		= 1 << 1,	/* provide optional reply for SET or ACT requests */
+	ETHTOOL_FLAG_STATS		= 1 << 2,	/* request statistics, if supported by the driver */
+};
 
 #define ETHTOOL_FLAG_ALL (ETHTOOL_FLAG_COMPACT_BITSETS | \
 			  ETHTOOL_FLAG_OMIT_REPLY | \