ARM: dts: aspeed: Add I2C buses

Now with an upstream i2c bus driver, we can add  the 14 i2c buses that
exist in ASPEED G4 and G5 generation SoCs.

It also adds aliases for the 14 built-in I2C busses to ensure userspace
sees the numbering staring from zero and counting up.

Acked-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>