platform/chrome: Fix i2c-designware adapter name

Commit d80d1341

 ("i2c: designware: Move common probe code into
i2c_dw_probe()") caused the I2C adapter lookup code here to fail for PCI
enumerated i2c-designware because commit changed the adapter name but
didn't update it here.

Fix the I2C adapter lookup by using the "Synopsys DesignWare I2C adapter"
name.

Reported-by: Jeremiah Mahler <jmmahler@gmail.com>
Fixes: d80d1341

 ("i2c: designware: Move common probe code into i2c_dw_probe()")
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Olof Johansson <olof@lixom.net>