Revert "i2c: designware: do not disable adapter after transfer"

This reverts commit 0317e6c0

.

Srinivas reported recently touchscreen and touchpad stopped working in
Haswell based machine in Linux 4.9-rc series with timeout errors from
i2c_designware:

[   16.508013] i2c_designware INT33C3:00: controller timed out
[   16.508302] i2c_hid i2c-MSFT0001:02: failed to change power setting.
[   17.532016] i2c_designware INT33C3:00: controller timed out
[   18.556022] i2c_designware INT33C3:00: controller timed out
[   18.556315] i2c_hid i2c-ATML1000:00: failed to retrieve report from device.

I managed to reproduce similar errors on another Haswell based machine
where touchscreen initialization fails maybe in every 1/5 - 1/2 boots.
Since root cause for these errors is not clear yet and debugging is
ongoing it's better to revert this commit as we are near to release.

Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>