Patch from Martin Bligh.

"This mainly changes the PLAT_MY_MACRO_IS_ALL_CAPS() stuff to be
 normal_macro(), and takes out some unnecessary redirection of function
 names.  No functionality changes, nothing touched outside i386
 discontigmem ...  just makes code readable.  Rumour has it that the
 PLAT_* stuff came from IRIX - I don't see that as a good reason to make
 the Linux code unreadable.  Tested on 16-way NUMA-Q."