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

This patch changes the type of the third parameter 'length' of the 
raw_send_hdrinc() function from 'int' to 'size_t'.
This makes sense since this function is only ever called from one 
location, and the value passed as the third parameter in that location is 
itself of type size_t, so this makes the recieving functions parameter 
type match. Also, inside raw_send_hdrinc() the 'length' variable is 
used in comparisons with unsigned values and passed as parameter to 
functions expecting unsigned values (it's used in a single comparison with 
a signed value, but that one can never actually be negative so the patch 
also casts that one to size_t to stop gcc worrying, and it is passed in a 
single instance to memcpy_fromiovecend() which expects a signed int, but 
as far as I can see that's not a problem since the value of 'length' 
shouldn't ever exceed the value of a signed int).

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>