pci: msm: Add support for NTN3 switch i2c client operations

NTN3 switch requires register access over i2c when PCIe link
is not up. Add i2c control interface for a i2c client driver.
This i2c control interface registers with a i2c client driver
and provides client specific callbacks for read, write, reset
and register dump operations.i2c control interface can support
one i2c client per root port.

Change-Id: I9e5f91cab4fd2bb2c6274ad0317fad4279db6958
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>