net: ping: remove some sparse errors

net/ipv4/sysctl_net_ipv4.c:78:6: warning: symbol 'inet_get_ping_group_range_table'
was not declared. Should it be static?

net/ipv4/sysctl_net_ipv4.c:119:31: warning: incorrect type in argument 2
(different signedness)
net/ipv4/sysctl_net_ipv4.c:119:31: expected int *range
net/ipv4/sysctl_net_ipv4.c:119:31: got unsigned int *<noident>

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>