Allwinner source tree cleanup

[manu_bidouilliste.com]

Summary

This clean the way the allwinner files are ordered.
This will help include other allwinner SoCs.
All drivers that support soc variant (gpio for example) are in sys/arm/allwinner and prefixed by aw_ .
All drivers that support on soc (even if it's used in multiple soc) are in the subfolder of the soc.
For example:
Our mmc driver is compatible with sun4i-a10-mmc and sun5i-a13-mmc so it is in sys/arm/allwinner/aw_mmc.c
Our ahci driver is compatible with sun4i-a10-ahci and even if it's also used in a20 it's is sys/arm/allwinner/a10/a10_ahci.c

This has no functional changes.

Test Plan

Apply and verify that kernels compile cleanly (A10, A20 and CUBIEBOARD).

[manu_bidouilliste.com]

Update diff due to recent changes in -HEAD.

[manu_bidouilliste.com]

We still haven't settled on the name convention (if we use SoC name or the allwinner code name sunXi), discussion is still open.

[andrew]

This needs an update for the recent Allwinner changes

[manu_bidouilliste.com]

I will provide a new one once 11 is branched.