subr_hal.c: implement WRITE_PORT_BUFFER_xxx() and READ_PORT_BUFFER_xxx()

subr_hal.c: implement WRITE_PORT_BUFFER_xxx() and READ_PORT_BUFFER_xxx()
subr_ndis.c: implement NdisDprAllocatePacket() and NdisDprFreePacket()
(which are aliased to NdisAllocatePacket() and NdisFreePacket()), and
bump the value we return in ndis_mapreg_cnt() to something ridiculously
large, since some drivers apparently expect to be able to allocate
way more than just 64.

These changes allow the Level 1 1000baseSX driver to work for
the following card:

ndis0: <SMC TigerCard 1000 Adapter> port 0xe000-0xe0ff mem 0xda004000-0xda0043ff irq 10 at device 9.0 on pci0
ndis0: Ethernet address: 00:e0:29:6f:cc:04

This is already supported by the lge(4) driver, but I decided
to take a try at making the Windows driver that came with it work too,
since I still had the floppy diskette for it lying around.