uboot-phytec

mux: mux-uclass: Don't print error msg if autoprobe is not requested

Its not necessary that mux node needs to be autoprobed. Hence, its not
fatal not have u-boot,mux-autoprobe in DT hence reduce error/printf()
message to dev_info()

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>