Remove external/ms-tpm-20-ref/.gitmodules and submodule directories am: 5d68d01a1a am: fac045177b am: ef87020c15 am: 3b84342fbf am: d45b3fbbca

Original change: https://android-review.googlesource.com/c/platform/external/ms-tpm-20-ref/+/1830606

Change-Id: I90e4f6e31e2f40e97c532e5c48956e974f0c810c