package/chrony: fix systemd service

Fixes the systemd service, the binary is located at /usr/sbin not
/usr/bin.

Signed-off-by: Christian Stewart <christian@paral.in>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/chrony/chrony.service

@@ -4,7 +4,7 @@ After=syslog.target network.target
 Conflicts=systemd-timesyncd.service
 
 [Service]
-ExecStart=/usr/bin/chronyd -n
+ExecStart=/usr/sbin/chronyd -n
 Restart=always
 
 [Install]