i2c: i2c-designware-platdrv: Cleanup setting of the adapter number

i2c-designware-platdrv assumes that if the pdev has an apci-companion
it should use a dynamic adapter-nr and otherwise it will use pdev->id
as adapter-nr.

Before this commit the setting of the adapter.nr was somewhat convoluted,
in the acpi_companion case it was set from dw_i2c_acpi_configure, in the
non acpi_companion case it was set from dw_i2c_set_fifo_size based on
tx_fifo_depth not being set yet indicating that dw_i2c_acpi_configure was
not executed.

This cleans this up, directly setting the adapter-nr from
dw_i2c_plat_probe for both cases.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>