memory.lua: Added module_init() to mlockall() at module-load time.

Previously the memory.lua API relied on mlockall() to have already
been called elsewhere.
memory.lua: Verbose error messages on physical address resolution failures.

Example:

      0xc0a0a000 did not resolve with active DMA regions:
      0x1ac00000 - 0x1ae00000 [2048 KB] (no match)
      0x1ae00000 - 0x1b000000 [2048 KB] (no match)
      0x1b000000 - 0x1b200000 [2048 KB] (no match)
      0x1b200000 - 0x1b400000 [2048 KB] (no match)
      0x1b400000 - 0x1b600000 [2048 KB] (no match)
      0x1b600000 - 0x1b800000 [2048 KB] (no match)
    memory.lua:123: Failed to resolve physical address of 0xc0a0a000