ntpd: fix compilation warnings

GCC complained about since_last_update being set but not used.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
ntpd: remove now unnecessary check for IP_PKTINFO definition

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
top.c: fix compilation warnings

pfd[1] is unused

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>