Description: [fix]ftruncate bugfix

Bug: #I3NEVN
Test:

fs/fat/os_adapt/fatfs.c

@@ -806,7 +806,10 @@ static FRESULT realloc_cluster(FILINFO *finfo, FFOBJID *obj, FSIZE_t size)
     if ((cclust == BAD_CLUSTER) || (cclust == DISK_ERROR)) {
         return FR_DISK_ERR;
     }
-    if (cclust != END_OF_FILE) { /* Remove extra cluster if existing */
+    if ((obj->fs->fs_type == FS_FAT12 && cclust != FAT12_END_OF_FILE) ||
+        (obj->fs->fs_type == FS_FAT16 && cclust != FAT16_END_OF_FILE) ||
+        (obj->fs->fs_type == FS_FAT32 && cclust != FAT32_END_OF_FILE)) {
+        /* Remove extra cluster if existing */
         result = remove_chain(obj, cclust, pclust);
         if (result != FR_OK) {
             return result;

fs/fat/os_adapt/fatfs.h

@@ -55,7 +55,9 @@ extern "C" {
 #define FAT32_MAXSIZE          0x100000000
 #define BAD_CLUSTER            0x7FFFFFFF
 #define DISK_ERROR             0xFFFFFFFF
-#define END_OF_FILE            0x0FFFFFFF
+#define FAT12_END_OF_FILE      0x00000FFF
+#define FAT16_END_OF_FILE      0x0000FFFF
+#define FAT32_END_OF_FILE      0x0FFFFFFF
 #define FAT_ERROR              (-1)
 
 /* MBR */