i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoin...

i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoint of pci1xxxx switch

Microchip pci1xxxx is an unmanaged PCIe3.1a Switch for Consumer,
Industrial and Automotive applications. This switch has multiple
downstream ports. In one of the Switch's Downstream port, there
is a multifunction endpoint for peripherals which includes an I2C
host controller. The I2C function in the endpoint operates at 100KHz,
400KHz and 1 MHz and has buffer depth of 128 bytes.
This patch provides the I2C controller driver for the I2C function
of the switch.

Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>