[IPV4]: [1/4] signed vs unsigned cleanup in net/ipv4/raw.c

This patch silences these two gcc -W warnings in net/ipv4/raw.c :

net/ipv4/raw.c:517: warning: signed and unsigned type in conditional expression
net/ipv4/raw.c:613: warning: signed and unsigned type in conditional expression

It doesn't change the behaviour of the code, simply writes the conditional 
expression with plain 'if()' syntax instead of '? :' , but since this 
breaks it into sepperate statements gcc no longer complains about having 
both a signed and unsigned value in the same conditional expression.

Signed-off-by: David S. Miller <davem@davemloft.net>