ntp: make socket resume timeout configurable

In some cases even the new timeout of 1 millisecond is not sufficient to
get all HW TX timestamps. Add a new directive to allow users to
specify longer timeouts.

conf.h

@@ -154,6 +154,7 @@ typedef struct {
 } CNF_HwTsInterface;
 
 extern int CNF_GetHwTsInterface(unsigned int index, CNF_HwTsInterface **iface);
+extern double CNF_GetHwTsTimeout(void);
 
 extern int CNF_GetPtpPort(void);