Preferred fix for Xen page-aligned bug

Hi Ingo,

My preferred fix for the Xen page-aligned bss bug you found is this:

1. Put the __page_aligned_data/bss fix into the x86 tree
2. Adjust all the x86 uses of page-aligned data/bss to use it (thereby fixing the Xen bug)
3. When all that hits linux-2.6.git, update sh and powerpc.

Patches follow for core+x86.

J