Crypto: Update to Mbed TLS 3.6.1

Update the CMake checkout dependency and re-align the
headers to the ones available in Mbed TLS 3.6.1.

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I681df1f2662c55b7aaf7eed2642b7ce3eeae8192
diff --git a/interface/include/mbedtls/bignum.h b/interface/include/mbedtls/bignum.h
index 71d7b97..8367cd3 100644
--- a/interface/include/mbedtls/bignum.h
+++ b/interface/include/mbedtls/bignum.h
@@ -880,7 +880,7 @@
                         mbedtls_mpi_sint b);
 
 /**
- * \brief          Perform a sliding-window exponentiation: X = A^E mod N
+ * \brief          Perform a modular exponentiation: X = A^E mod N
  *
  * \param X        The destination MPI. This must point to an initialized MPI.
  *                 This must not alias E or N.