dtb: amd: Misc changes for I2C device nodes

Add new i2c1 device node, and fix the incorrect clock frequency.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Olof Johansson <olof@lixom.net>