* misc: Implement address space size workarounds
This adds code to support userland with less than 39 bits of address
space available by testing reserving multiple sizes and reducing
guess address space when needed.
This is required for ARM64 support when the kernel is
configured to use 63..39 bits for kernel space.(meaning only 38 bits is available to userland)
* Address comments
* Fix 32 bits address space support and address more comments
