f2fs: Revert duplicate F2FS_MAX_SEGMENT

This reverts commit e4f60027 ("f2fs: sanity check segment
count"). This change was already present and the new commit
added a redundant declaration for F2FS_MAX_SEGMENT.

Change-Id: Ie9a1d2b255fb20fcf2d4237e661430a39d8626ef
Signed-off-by: Dennis Cagle <dcagle@codeaurora.org>