ethtool: Call ethtool's get/set_settings callbacks with cleaned data

This makes sure that when a driver calls the ethtool's
get/set_settings() callback of another driver, the data passed to it
is clean. This guarantees that speed_hi will be zeroed correctly if
the called callback doesn't explicitely set it: we are sure we don't
get a corrupted speed from the underlying driver. We also take care of
setting the cmd field appropriately (ETHTOOL_GSET/SSET).

This applies to dev_ethtool_get_settings(), which now makes sure it
sets up that ethtool command parameter correctly before passing it to
drivers. This also means that whoever calls dev_ethtool_get_settings()
does not have to clean the ethtool command parameter. This function
also becomes an exported symbol instead of an inline.

All drivers visible to make allyesconfig under x86_64 have been
updated.

Signed-off-by: David Decotigny <decot@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/mii.c b/drivers/net/mii.c
index 0a6c6a2..05acca7 100644
--- a/drivers/net/mii.c
+++ b/drivers/net/mii.c
@@ -58,6 +58,9 @@
  * @mii: MII interface
  * @ecmd: requested ethtool_cmd
  *
+ * The @ecmd parameter is expected to have been cleared before calling
+ * mii_ethtool_gset().
+ *
  * Returns 0 for success, negative on error.
  */
 int mii_ethtool_gset(struct mii_if_info *mii, struct ethtool_cmd *ecmd)