gnu: ethtool: Update to 5.6.

* gnu/packages/networking.scm (ethtool): Update to 5.6.
[native-inputs]: Add pkg-config.
[inputs]: Add libmnl.

gnu/packages/networking.scm

@@ -588,15 +588,19 @@ receiving NDP messages.")
 (define-public ethtool
   (package
     (name "ethtool")
-    (version "5.4")
+    (version "5.6")
     (source (origin
               (method url-fetch)
               (uri (string-append "mirror://kernel.org/software/network/"
                                   "ethtool/ethtool-" version ".tar.xz"))
               (sha256
                (base32
-                "0srbqp4a3x9ryrbm5q854375y04ni8j0bmsrl89nmsyn4x4ixy12"))))
+                "159r0hwax0qs5diayw2glxshqxrigk0v67hgmbq56ldddm91n3ya"))))
     (build-system gnu-build-system)
+    (native-inputs
+     `(("pkg-config" ,pkg-config)))
+    (inputs
+     `(("libmnl" ,libmnl)))
     (home-page "https://www.kernel.org/pub/software/network/ethtool/")
     (synopsis "Display or change Ethernet device settings")
     (description