[PATCH v5 0/2] i2c: aspeed: added driver for Aspeed I2C

[Brendan Higgins]

Addressed comments from:
  - Cedric in: https://www.spinics.net/lists/devicetree/msg151685.html
  - Kachalov in: https://www.spinics.net/lists/devicetree/msg151819.html
  - Vladimir in: https://www.spinics.net/lists/devicetree/msg152454.html

Changes since previous update:
  - Removed irq_chip used to multiplex IRQ and replaced it with dummy_irq_chip
    along with some other IRQ cleanup.
  - Addressed comments from Cedric, and Vladimir, mostly stylistic things and
    using devm managed resources.
  - Increased max clock frequency before the bus is put in HighSpeed mode, as
    per Kachalov's comment.

Changes have been tested on the Aspeed evaluation board as before.