defconfig: 8084: Enable F2FS

F2FS is a file system used for NAND flash memory-based storage devices.
Enable this filesystem for APQ8084.

Change-Id: I89ffa93d3d5e3787eb11903d1c2b66019434def9
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>