Fix code that calculates the dcoFrequency when the si570 is calibrated for 10mhz

[sarfata]

Mac - AE5PH reported:

Here are the register values I obtained from my Si570:

Register[7] = ad
Register[8] = 42
Register[9] = a8
Register[10] = db
Register[11] = fe
Register[12] = 17
HS = 9, N1 = 54
Reference Frequency (hex): 2A8DBFE17
Reference Frequency (double): 42.553710
Crystal Frequency (long int): 114208608 (Hz)

Version 0.03 would not work properly until I made the following
code change in Si570.cpp:

uint64_t Si570::getRfReq() {
  uint64_t dcoFrequency = 0;
//  dcoFrequency =  (uint64_t)(this->dco_reg[8] & 0x3F) << 32;
//  dcoFrequency |= (uint64_t)this->dco_reg[9]  << 24;
//  dcoFrequency |= (uint64_t)this->dco_reg[10] << 16;
//  dcoFrequency |= this->dco_reg[11] << 8;
//  dcoFrequency |= this->dco_reg[12];
  dcoFrequency = (uint64_t)(dco_reg[8] & 0x3F);
  dcoFrequency = (dcoFrequency << 8) | (uint64_t) dco_reg[9];
  dcoFrequency = (dcoFrequency << 8) | (uint64_t) dco_reg[10];
  dcoFrequency = (dcoFrequency << 8) | (uint64_t) dco_reg[11];
  dcoFrequency = (dcoFrequency << 8) | (uint64_t) dco_reg[12];
  return dcoFrequency;
}

It appears that the most significant bits (above bit 31) disappear. Perhaps unsigned, 64-bit shifts are not working properly.
As expected, I made the following change code change in radiono.ino:

  //vfo = new Si570(SI570_I2C_ADDRESS, 56320000);
  vfo = new Si570(SI570_I2C_ADDRESS, 10000000);

After this was done, I was able to change frequency and measure
frequency changes on the Si570. For example, setting the frequency
to 7.0000 MHz on the display yielded a Si570 frequency of 27 MHz.