fs: change to new flag variable

Replace EXTRA_CFLAGS with ccflags-y. And change ntfs-objs to ntfs-y
for cleaner conditional inclusion.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>