MIPS: JZ4770: GCW0: Remove option to use hardware I2C

This can be re-introduced once we're on DT.
MIPS: JZ4770: Remove platform support for hardware I2C

This can be re-introduced once we're on DT.
i2c: Remove JZ4770 I2C driver from Ingenic

We are using the i2c-gpio driver instead. If we want to make use of the
hardware I2C support, we can switch to the JZ4780 driver once we're on
a shared source tree, or modernize this driver to work with DT.