i2c: mux: Inherit retry count and timeout from parent for muxed bus

If a muxed i2c bus gets created the default retry count and
timeout of the muxed bus is zero. Hence it it possible that you
end up with a situation where the parent controller sets a default
retry count and timeout which gets applied and used while the muxed
bus (using the same controller) has a default retry count of zero
and a default timeout of 1s (set in i2c_add_adapter()). This can be
solved by initializing the retry count and timeout of the muxed
bus with the values used by the the parent at creation time.

Signed-off-by: Elie De Brauwer <eliedebrauwer@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>