fs: reimplement exfat to hopefully fix compile errors

https://github.com/dorimanx/exfat-nofuse
fs: f2fs: fix build errors

It still needs in reimplementing
Revert "defconfig: temporarily disable F2FS and exFat"

This reverts commit f3b6fc55188e8b1d1deed22f3bb4c2c83830ced9.
various drivers: fixed memleaks

https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?h=linux-3.2.y&qt=grep&q=memleak