net: Use PTR_RET rather than if(IS_ERR(.. [1]

The semantic patch that makes this change is available
in scripts/coccinelle/api/ptr_ret.cocci.

More information about semantic patching is available at
http://coccinelle.lip6.fr/



Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: David S. Miller <davem@davemloft.net>