Add hidden setting to turn off QMUX
Add hidden setting to turn off QMUX

QMUX is not supported on Qualcomm ThreadX platforms.

Resolves: LE-13554
Change-Id: I90ef56f69519e16eed82f4970196bb5f0aa7be4c

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af