The FAT specification [1] requires that for a '..' directory entry pointing
to the root directory the fields DIR_FstClusHi and DIR_FstClusLo are 0.
[1] Microsoft FAT Specification, Microsoft Corporation, August 30 2005
Fixes: 31a18d570d ("fs: fat: support mkdir")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>