fix typos length、there、necessary

close https://gitee.com/openharmony/kernel_liteos_a/issues/I3RSY0

FAT12/FAT16 partition has no FSINFO sector storing the free cluster number,
so scanning the FAT is necessary to get the free clusters nums.

Close #I3Q0VS

if fatfs_mkfs returns a error, format may return without drop the vnode mutex, which may cause deadlock

Close #I3OFAY

The errno of unrecognized fat filesystem changes from ENOENT to ENOTSUP.

Close #I3O8IF

When fatfs_lookup find a vnode from hashlist, the field parent of vnode should be updated,
because the old parent may be reclaimed.

Close #I3NNFA

Bug: #I3NEVN
Test:

Change-Id: I052d930d54e63179b17b77f02c107a015f3cfc3f

Bug: #I3J1IC
Test: io test 1000 time

1. Bcache block with high mem address is after lower mem address in RCU list when initing bcache.
2. Format will clear the bcache before writing the FAT.
3. The fatfs_readdir use the bcache writing block to reduce the chance of data switching out
4. Add performance analysing macron switch

Change-Id: I8fbc48418509d2e660d725d2c265266e931c26f8

Change-Id: Ic443742e125915f0e5332a338dedea5c40348928

Change-Id: I9c49073ad2bbd668102d20da8ff7a8d680890deb

Feature or Bugfix:Feature
Binary Source:Huawei
PrivateCode(Yes/No):Yes

Change-Id: I175d2648bc6f9078c34de2c0a5c93fda10b86c47
ChangeID:13306388

Change-Id: Ia6c1f6302407a707b3ec9b805f4c92d8a7970b86