mm, vmalloc: export vmap_area_list, instead of vmlist

mm, vmalloc: export vmap_area_list, instead of vmlist

Although our intention is to unexport internal structure entirely, but
there is one exception for kexec.  kexec dumps address of vmlist and
makedumpfile uses this information.

We are about to remove vmlist, then another way to retrieve information
of vmalloc layer is needed for makedumpfile.  For this purpose, we
export vmap_area_list, instead of vmlist.

Signed-off-by: Joonsoo Kim <[email protected]>
Signed-off-by: Joonsoo Kim <[email protected]>
Cc: Eric Biederman <[email protected]>
Cc: Dave Anderson <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Atsushi Kumagai <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>