Remove external/libkmsxx/.gitmodules. am: 906a6c9a6a am: dffc424e7e am: 64b93dc17a

Original change: https://android-review.googlesource.com/c/platform/external/libkmsxx/+/1830607

Change-Id: I41fb20e5ec2698a5ba683908b11af285396f9c71