[NET_SCHED]: cls_tcindex: fix compatibility breakage

Userspace uses an integer for TCA_TCINDEX_SHIFT, the kernel was changed
to expect and use a u16 value in 2.6.11, which broke compatibility on
big endian machines. Change back to use int.

Reported by Ole Reinartz <ole.reinartz@gmx.de>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>