Merged in AVyhovanec/nuttx (pull request #564)

FAT. Effectively handles the situation when a new file position is within the current sector.

* Find begin of the next token

* EOL

* revert

* Accelerates the work of the FS with a multitude of operations to write small pieces of data within the current sector.

Approved-by: Gregory Nutt <gnutt@nuttx.org>