net: macb: Remove unnecessary alignment check for TSO

net: macb: Remove unnecessary alignment check for TSO

[ Upstream commit 41c1ef978c8d0259c6636e6d2d854777e92650eb ]

The IP TSO implementation does NOT require the length to be a
multiple of 8. That is only a requirement for UFO as per IP
documentation. Hence, exit macb_features_check function in the
beginning if the protocol is not UDP. Only when it is UDP,
proceed further to the alignment checks. Update comments to
reflect the same. Also remove dead code checking for protocol
TCP when calculating header length.

Fixes: 1629dd4f763c ("cadence: Add LSO support.")
Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>