apps/bleprph: Make device name configurable

apps/bleprph/src/main.c

@@ -323,10 +323,6 @@ main(void)
     rc = gatt_svr_init();
     assert(rc == 0);
 
-    /* Set the default device name. */
-    rc = ble_svc_gap_device_name_set("nimble-bleprph");
-    assert(rc == 0);
-
 #if MYNEWT_VAL(BLE_SVC_DIS_FIRMWARE_REVISION_READ_PERM) >= 0
     /* Set firmware version in DIS */
     imgr_my_version(&ver);

apps/bleprph/syscfg.yml

@@ -64,3 +64,5 @@ syscfg.vals:
     # values.
     MSYS_1_BLOCK_COUNT: 22
     MSYS_1_BLOCK_SIZE: 110
+
+    BLE_SVC_GAP_DEVICE_NAME: '"nimble-bleprph"'