host: libbladeRF_test: fix printf of int64_t value

Fixes build failure on macOS

host/libraries/libbladeRF_test/test_repeater/src/repeater.c

@@ -62,6 +62,7 @@

#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <string.h>
#include <pthread.h>
#include <libbladeRF.h>
@@ -518,7 +519,8 @@ static int init_device(struct repeater *repeater, struct repeater_config *config
        memcpy(&repeater->gain_range_tx, gain_ptr,
                                        sizeof(struct bladerf_range));

        printf("TX gain range is: [%ld, %ld]\r\n", repeater->gain_range_tx.min,
        printf("TX gain range is: [%"PRIi64", %"PRIi64"]\r\n",
                                           repeater->gain_range_tx.min,
                                           repeater->gain_range_tx.max);
    }

@@ -542,7 +544,8 @@ static int init_device(struct repeater *repeater, struct repeater_config *config
        memcpy(&repeater->gain_range_rx, gain_ptr,
                                        sizeof(struct bladerf_range));

        printf("RX gain range is: [%ld, %ld]\r\n", repeater->gain_range_rx.min,
        printf("RX gain range is: [%"PRIi64", %"PRIi64"]\r\n",
                                           repeater->gain_range_rx.min,
                                           repeater->gain_range_rx.max);
    }