i2c: designware: Uniform initialization flow for polling mode

Currently initialization flow in i2c_dw_probe_master() skips a few steps
and has code duplication for polling mode implementation.

Simplify this by adding a new ACCESS_POLLING flag that is set for those
two platforms that currently use polling mode and use it to skip
interrupt handler setup.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jiawen Wu <jiawenwu@trustnetic.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>