Move the hardware PMD and PTE page table definitions from pgtable.h
into pgtable-hwdef.h, and include pgtable-hwdef.h as necessary.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Both pmd_populate variants set two pmd entries before
ensuring that they are flushed from the cache.  Separate
this functionality into __pmd_populate().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!