The old and new address parameters passed to the mremap system
call must be page size aligned. On AArch64, the page size can
only be correctly determined at run time. This fixes the following
errors for CRIU on AArch64 kernels with CONFIG_ARM64_64K_PAGES=y.

      call mremap(0x3ffb7d50000, 8192, 8192, MAYMOVE | FIXED, 0x2a000)
  Error (rst-malloc.c:201): Can't mremap rst mem: Invalid argument

      call mremap(0x3ffb7d90000, 8192, 8192, MAYMOVE | FIXED, 0x32000)
  Error (rst-malloc.c:201): Can't mremap rst mem: Invalid argument
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>