fusion: remove dead MTRR code

If and when this gets enabled the driver could should split
up IO memory space properly and that is quite a bit of work.
Just remove the uncommented dead MTRR code then.

There are a few motivations for this:

a) Take advantage of PAT when available

b) Help bury MTRR code away, MTRR is architecture specific and on
   x86 its replaced by PAT

c) Help with the goal of eventually using _PAGE_CACHE_UC over
   _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
   de33c442 titled "x86 PAT: fix performance drop for glx,
   use UC minus for ioremap(), ioremap_nocache() and
   pci_mmap_page_range()")

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Acked-by: Sreekanth Reddy <ureekanth.reddy@avagotech.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>