[PATCH] fix write combining on ia64

[Jesse B. <jb...@en...>]

Some ia64 platforms may not support write combining on all type of memory, so 
we need to consult the EFI memory map before we try to set the write combine 
attribute of a page.  This patch will try to map a page write combined if 
it's not an AGP page and the EFI memory map says it's ok, otherwise it falls 
back to a regular, uncached mapping.  Can someone please apply this to the 
drm tree?

Thanks,
Jesse