allwinner: add I2C glue driver

Allwinner 64-bit SoCs all use the Mentor Graphics MI2CV I2C controller
core, with inverted clear quirk.

Add a glue driver for this.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
diff --git a/maintainers.rst b/maintainers.rst
index 969d5e5..3f64b83 100644
--- a/maintainers.rst
+++ b/maintainers.rst
@@ -24,6 +24,7 @@
 :G: `smaeul`_
 :F: docs/plat/allwinner.rst
 :F: plat/allwinner/
+:F: drivers/allwinner/
 
 Armv7-A architecture port
 -------------------------