compat: add ndo_do_ioctl()

compat: add ndo_do_ioctl()

This helps reduce the delta on backporting calls of the
netdev's ioctl callback. Instead of ifdef'ing on where
the ioctl callback lies in different kernels we take
care of that for all kernels.

This lets us for example change this backport:

	@@ -925,8 +954,13 @@ static int wireless_process_ioctl(struct
				return private(dev, iwr, cmd, info, handler);
		}
		/* Old driver API : call driver ioctl handler */
	+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,29))
		if (dev->netdev_ops->ndo_do_ioctl)
			return dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
	+#else
	+       if (dev->do_ioctl)
	+               return dev->do_ioctl(dev, ifr, cmd);
	+#endif
		return -EOPNOTSUPP;
	 }

To this:

	--- a/net/wireless/wext-core.c
	+++ b/net/wireless/wext-core.c
	@@ -925,9 +925,7 @@ static int wireless_process_ioctl(struct
				return private(dev, iwr, cmd, info, handler);
		}
		/* Old driver API : call driver ioctl handler */
	-       if (dev->netdev_ops->ndo_do_ioctl)
	-               return dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
	-       return -EOPNOTSUPP;
	+       return ndo_do_ioctl(dev, ifr, cmd);
	 }

	 /* If command is `set a parameter', or `get the encoding parameters',

This shows more deletions than additions. This is what we want.

If we add ndo_do_ioctl() upstream then this would require 0 delta!

Trying kernel                  3.4.0-030400rc1-generic	[OK]
Trying kernel                  3.3.0-030300rc2-generic	[OK]
Trying kernel                     3.2.2-030202-generic	[OK]
Trying kernel                    3.1.10-030110-generic	[OK]
Trying kernel                    3.0.18-030018-generic	[OK]
Trying kernel                  2.6.39-02063904-generic	[OK]
Trying kernel                  2.6.38-02063808-generic	[OK]
Trying kernel                  2.6.37-02063706-generic	[OK]
Trying kernel                  2.6.36-02063604-generic	[OK]
Trying kernel                  2.6.35-02063512-generic	[OK]
Trying kernel                  2.6.34-02063410-generic	[OK]
Trying kernel                  2.6.33-02063305-generic	[OK]
Trying kernel                  2.6.32-02063255-generic	[OK]
Trying kernel                  2.6.31-02063113-generic	[OK]
Trying kernel                  2.6.30-02063010-generic	[OK]
Trying kernel                  2.6.29-02062906-generic	[OK]
Trying kernel                  2.6.28-02062810-generic	[OK]
Trying kernel                    2.6.27-020627-generic	[OK]
Trying kernel                    2.6.26-020626-generic	[OK]
Trying kernel                    2.6.25-020625-generic	[OK]
Trying kernel                    2.6.24-020624-generic	[OK]

Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>