net/core/sock.c: quiet sparse noise

In sock_getsockopt the symbol 'lv' is declared as an
unsigned int type, probably due to sizeof returning a
size_t which is really an unsigned int.

This produces a sparse warning for SO_PEERNAME due to
the sock->ops->getname() call:

warning: incorrect type in argument 3 (different signedness)
   expected int *sockaddr_len
   got unsigned int *<noident>

Quiet the warning by changing the type of 'lv' to an int.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: David S. Miller <davem@davemloft.net>