Remove Cargo.lock for optee-utee and optee-teec

As per Cargo's documentation[1], only binary crates should check in
Cargo.lock. Library crates should not, since dependents will do their
own version resolution anyway.

This mostly reverts commit 0438ca9 ("Add Cargo.lock for optee-utee
and optee-teec").

[1] https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

Author: tchebb

.gitignore

@@ -15,6 +15,8 @@
 # specific language governing permissions and limitations
 # under the License.
 
+/optee-utee/Cargo.lock
+/optee-teec/Cargo.lock
 /examples/**/proto/Cargo.lock
 *.rs.bk
 .user_ta_header.o.d