Florian Heinz built an a.out binary that could map bss from 0x0 to
0xc0000000, and setup_arg_pages() would be unhappt in insert_vma_struct
because the arg pages overlapped.  This just checks before inserting,
and bails out if it would overlap.
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>