ipq807x: fat: Fix overflow issue

As per FAT spec, the number of sectors can be more than
clusters, as clusters starts from databegin.
So check cluster overflow against total clusters.

The FAT at present in u-boot lacks a lot, such as
support for long file names, subdir etc.
The mini dump was using more than 8 character name,
changed that one too.

Change-Id: Icfae6d955dd93432b3d33d7c0b9a724382d87185
Signed-off-by: Manoharan Vijaya Raghavan <mraghava@codeaurora.org>
3 files changed