Add ACC_CALIB arming disabled reason if ACC is required but not calibrated

Checks various features, modes, and OSD elements to determine if ACC is needed. Generates an arming disabled warning if ACC calibration has never been completed.

src/main/osd/osd.c

@@ -136,6 +136,10 @@ PG_REGISTER_WITH_RESET_FN(osdConfig_t, osdConfig, PG_OSD_CONFIG, 6);
 // be shown on the the post-flight statistics page.
 // If you reorder the stats it's likely that you'll need to make likewise updates
 // to the unit tests.
+
+// If adding new stats, please add to the osdStatsNeedAccelerometer() function
+// if the statistic utilizes the accelerometer.
+//
 const osd_stats_e osdStatsDisplayOrder[OSD_STAT_COUNT] = {
     OSD_STAT_RTC_DATE_TIME,
     OSD_STAT_TIMER_1,
@@ -950,4 +954,20 @@ statistic_t *osdGetStats(void)
 {
     return &stats;
 }
+
+#ifdef USE_ACC
+// Determine if there are any enabled stats that need
+// the ACC (currently only MAX_G_FORCE).
+static bool osdStatsNeedAccelerometer(void)
+{
+    return osdStatGetState(OSD_STAT_MAX_G_FORCE);
+}
+
+// Check if any enabled elements or stats need the ACC
+bool osdNeedsAccelerometer(void)
+{
+    return osdStatsNeedAccelerometer() || osdElementsNeedAccelerometer();
+}
+#endif // USE_ACC
+
 #endif // USE_OSD