i2c: muxes: Add support for TI PCA954X mux

Add support for common TI i2c mux which is available on ZynqMP zcu102
board.
DM i2c mux core code is selecting/deselecting bus before/after
every command is performed that's why only one channel is active at a
time. That's also the reason why deselect is just disable all available
channels.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>