ARM: dts: dra76x: Disable usb4_tm target module

usb4_tm is unsed on dra76 and accessing the module
with ti,sysc is causing a boot crash hence disable its target
module.

Fixes: 549fce06 ("ARM: dts: dra7: Add l4 interconnect hierarchy and ti-sysc data")
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>