i386-gdt-pda i386 gdt and pda updates

Hi Andrew,

This patch series adds to the end of the existing i386-gdt-cleanups patches:

	 allow-per-cpu-variables-to-be-page-aligned.patch
	 i386-gdt-cleanups-use-per-cpu-variables-for-gdt-pda.patch
	 i386-gdt-cleanups-use-per-cpu-gdt-immediately-upon-boot.patch
	 i386-gdt-cleanups-use-per-cpu-gdt-immediately-upon-boot-fix.patch
	 i386-gdt-cleanups-clean-up-cpu_init.patch
	 i386-gdt-cleanups-cleanup-gdt-access.patch
	 i386-gdt-cleanups-rename-boot_gdt_table-to-boot_gdt.patch
	+i386-gdt-cleanups-page-align-the-gdt.patch
	+i386-convert-pda-into-the-percpu-section.patch
	+lguest-use-percpu.patch
	+i386-cleanups-to-help-using-per-cpu-variables-from-asm.patch
	+percpu-define-per_cpu_offset.patch

The quick summary of each patch is:

i386-gdt-cleanups-page-align-the-gdt.patch

Make sure the GDT is page-aligned, which Xen requires, but it is generally helpful.

i386-convert-pda-into-the-percpu-section.patch

Remove the PDA as a separate entity, and use the normal per-cpu mechanism This still uses the PDA's underlying segment machinery to retain the same code-size and atomicity benefits that the PDA had.

lguest-use-percpu.patch

Fix lguest's initialization to skip PDA references.

i386-cleanups-to-help-using-per-cpu-variables-from-asm.patch

Add some tweaks to asm-i386/percpu.h to allow efficient access to per-cpu variables from assembler.

percpu-define-per_cpu_offset.patch

Define per_cpu_offset in asm-i386/percpu.h, to be consistent with asm-generic/percpu.h.

Thanks,
J