modules: hal_nxp: removing always empty zephyr_library

No sources were ever added to the `zephyr_library()` defined in
modules/hal_nxp/usb/CMakeLists.txt, thus removing this lib to avoid
the warning:

> No SOURCES given to Zephyr library: modules__hal_nxp__usb
>
> Excluding target from build.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>