ARM: dts: dra7: Fix duplicate USB4 target module node

With [1] USB4 target-module node got defined in dra74x.dtsi file.
However, the earlier definition in [2] was not removed, and this
duplication of the target module is causing boot failure on dra74
variant boards - dra7-evm, dra76-evm.

USB4 is only present in DRA74x variants, so keeping the entry in
dra74x.dtsi and removing it from the top level interconnect hierarchy
dra7-l4.dtsi file. This change makes the USB4 target module no longer
visible to AM5718, DRA71x and DRA72x so removing references to it in
their respective dts files.

[1]: commit c7b72abc ("ARM: OMAP2+: Drop legacy platform data for
dra7 dwc3")
[2]: commit 549fce06 ("ARM: dts: dra7: Add l4 interconnect
hierarchy and ti-sysc data")

Fixes: c7b72abc ("ARM: OMAP2+: Drop legacy platform data for dra7 dwc3")
Signed-off-by: Gowtham Tammana <g-tammana@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>