add fiemap.h to header-y

Include fiemap.h in header-y; it defines the interface for the
FS_IOC_FIEMAP file mapping ioctl.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>