mem: use address hint for mapping hugepages

mem: use address hint for mapping hugepages

Linux kernel uses a really high address as starting address for
serving mmaps calls. If there exist addressing limitations and
IOVA mode is VA, this starting address is likely too high for
those devices. However, it is possible to use a lower address in
the process virtual address space as with 64 bits there is a lot
of available space.

This patch adds an address hint as starting address for 64 bits
systems and increments the hint for next invocations. If the mmap
call does not use the hint address, repeat the mmap call using
the hint address incremented by page size.

Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>