Use upstream Linux, not sunxi-devel

The features we need should be upstream now.
Improved 1st-boot script

- Force initialisation of LVM volume
- Ensure SSH keys are always regenerated
- If LVM setup fails, don't retry
Add grant_map_identity_4.4 patches

This fixes sharing of the same physical page multiple times.
Merge pull request #13 from talex5/master

Use upstream Linux, not sunxi-devel