i2c: designware: Rework probe() to get clock a bit later

In order to be able to create missing clock for AMD (and in future possibly
others) we move getting clock for the device a bit later. Also make ACPI/DT
configuration in the same place depending on from where the device was
enumerated from.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>