Set system time so LittleFS can take over the real time

[Andreotti100]

Using this library resulted in wrong file time stamps, 1970 style.
So, I made a change:

#include <coredecls.h> // Needed for setting the right system time

void setTime(time_t t) {
#ifdef TIME_DRIFT_INFO
if(sysUnsyncedTime == 0)
sysUnsyncedTime = t; // store the time of the first call to set a valid Time
#endif

sysTime = (uint32_t)t;
nextSyncTime = (uint32_t)t + syncInterval;
Status = timeSet;
prevMillis = millis(); // restart counting from now (thanks to Korman for this fix)
tune_timeshift64((uint64_t)sysTime * 1000000ULL); // Take over the new time into the system time
}