Projectkk2glider/fatfs 0.12 (#3925)

* Re #3815: Disk cache: Write statistic added. Bigger disk cache. Show disk cache misses in CLI.

* Update to the latest FatFS R0.12b (all existing OpenTX patches have been already applied in upstream, only few ff.h modifications needed for simulator)

* Missing file

* SD card manager: do not show parent dir [..] for root directory

radio/src/disk_cache.cpp

@@ -86,6 +86,7 @@ DiskCache::DiskCache():
 {
   stats.noHits = 0;
   stats.noMisses = 0;
+  stats.noWrites = 0;
   blocks = new DiskCacheBlock[DISK_CACHE_BLOCKS_NUM];
 }
 
@@ -94,6 +95,7 @@ void DiskCache::clear()
   lastBlock = 0;
   stats.noHits = 0;
   stats.noMisses = 0;
+  stats.noWrites = 0;
   for (int n=0; n<DISK_CACHE_BLOCKS_NUM; ++n) {
     blocks[n].free();
   }
@@ -147,6 +149,7 @@ DRESULT DiskCache::read(BYTE drv, BYTE * buff, DWORD sector, UINT count)
 
 DRESULT DiskCache::write(BYTE drv, const BYTE* buff, DWORD sector, UINT count)
 {
+  ++stats.noWrites;
   for(int n=0; n < DISK_CACHE_BLOCKS_NUM; ++n) {
     blocks[n].free(sector, count);
   }