If the kernel symbols fit completely into the 2 MB alignment hole

If the kernel symbols fit completely into the 2 MB alignment hole
after kernel bss but before end of the image, the page tables used
the read-only mapping of the hole.  When booting a small non-generic
kernel, this resulted in a crash, while writing to the page tables
later.
Make sure that the page tables are created after esym and after
end.
OK mlarkin@ deraadt@