tests/subsys/usb: Don't test on native_posix

native_posix is now deprecated.
Building these tests in both native_sim and native_posix does not
improve coverage for the tests or subsystem but doubles CI time.
As anyhow native_posix will be removed all together in
2 releases, let's remove it already for these.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

tests/subsys/usb/os_desc/testcase.yaml

@@ -1,8 +1,6 @@
 tests:
   usb.osdesc:
     platform_allow:
-      - native_posix
-      - native_posix/native/64
       - native_sim
       - native_sim/native/64
       - frdm_k64f