i2c: designware: add reset ctrl to driver

Add code to look for a reset manager property. Specifically, look for the
reset-names of 'i2c'. A reset property is an optional feature, so only print
out a warning and do not fail if a reset property is not present.

If a reset property is discovered, then use it to deassert, thus bringing the
IP out of reset.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>