driver: fix issues reported by PVS-Studio

https://www.viva64.com/en/b/0790/#ID88049D3FA2
https://www.viva64.com/en/b/0790/#IDE0890EE01C
Reported in https://github.com/espressif/esp-idf/issues/6440

components/driver/ledc.c

@@ -942,15 +942,19 @@ static esp_err_t ledc_fade_channel_init_check(ledc_mode_t speed_mode, ledc_chann
     if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
 #if CONFIG_SPIRAM_USE_MALLOC
         s_ledc_fade_rec[speed_mode][channel] = (ledc_fade_t *) heap_caps_calloc(1, sizeof(ledc_fade_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
-        if (!s_ledc_fade_rec[speed_mode][channel]) {
+        if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
             ledc_fade_channel_deinit(speed_mode, channel);
-            return ESP_FAIL;
+            return ESP_ERR_NO_MEM;
         }
 
         memset(&s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem_storage, 0, sizeof(StaticQueue_t));
         s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem = xSemaphoreCreateBinaryStatic(&s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem_storage);
 #else
         s_ledc_fade_rec[speed_mode][channel] = (ledc_fade_t *) calloc(1, sizeof(ledc_fade_t));
+        if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
+            ledc_fade_channel_deinit(speed_mode, channel);
+            return ESP_ERR_NO_MEM;
+        }
         s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem = xSemaphoreCreateBinary();
 #endif
         s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux = xSemaphoreCreateMutex();

components/driver/sdio_slave.c

@@ -403,10 +403,6 @@ esp_err_t sdio_slave_start(void)
     critical_enter_recv();
     sdio_slave_hal_recv_start(context.hal);
     critical_exit_recv();
-    ret = ESP_OK;
-    if (ret != ESP_OK) {
-        return ret;
-    }
 
     sdio_slave_hal_set_ioready(context.hal, true);
     return ESP_OK;