LoRaPHY: Pass frequency set in rx_config() to caller

In AU/CN/US PHY, RX1 slot frequency is calculated in rx_config().
Since the caller is printing it to log, modify the frequency in
parameter structure so that the correct value will be printed.

features/lorawan/lorastack/phy/LoRaPHYAU915.cpp

@@ -355,6 +355,8 @@ bool LoRaPHYAU915::rx_config(rx_config_params_t *params)
         // Apply window 1 frequency
         frequency = AU915_FIRST_RX1_CHANNEL
                     + (params->channel % 8) * AU915_STEPWIDTH_RX1_CHANNEL;
+        // Caller may print the frequency to log so update it to match actual frequency
+        params->frequency = frequency;
     }
 
     // Read the physical datarate from the datarates table

features/lorawan/lorastack/phy/LoRaPHYCN470.cpp

@@ -377,6 +377,8 @@ bool LoRaPHYCN470::rx_config(rx_config_params_t *config)
     if (config->rx_slot == RX_SLOT_WIN_1) {
         // Apply window 1 frequency
         frequency = CN470_FIRST_RX1_CHANNEL + (config->channel % 48) * CN470_STEPWIDTH_RX1_CHANNEL;
+        // Caller may print the frequency to log so update it to match actual frequency
+        config->frequency = frequency;
     }
 
     // Read the physical datarate from the datarates table

features/lorawan/lorastack/phy/LoRaPHYUS915.cpp

@@ -374,6 +374,8 @@ bool LoRaPHYUS915::rx_config(rx_config_params_t *config)
     if (config->rx_slot == RX_SLOT_WIN_1) {
         // Apply window 1 frequency
         frequency = US915_FIRST_RX1_CHANNEL + (config->channel % 8) * US915_STEPWIDTH_RX1_CHANNEL;
+        // Caller may print the frequency to log so update it to match actual frequency
+        config->frequency = frequency;
     }
 
     // Read the physical datarate from the datarates table