Use MBEDTLS_PYTHON_EXECUTABLE

Change one occurrence of ${PYTHON} to ${MBEDTLS_PYTHON_EXECUTABLE}
and add implied ${MBEDTLS_PYTHON_EXECUTABLE} to the start of a
different command.

Signed-off-by: David Horstmann <[email protected]>

programs/psa/CMakeLists.txt

@@ -9,7 +9,7 @@ if(DEV_MODE)
         OUTPUT
             ${CMAKE_CURRENT_BINARY_DIR}/psa_constant_names_generated.c
         COMMAND
-            ${PYTHON}
+            ${MBEDTLS_PYTHON_EXECUTABLE}
                 ${CMAKE_CURRENT_SOURCE_DIR}/../../scripts/generate_psa_constants.py
                 ${CMAKE_CURRENT_BINARY_DIR}
         WORKING_DIRECTORY

tests/CMakeLists.txt

@@ -19,6 +19,7 @@ file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/suites)
 # Get base names for generated files (starting at "suites/")
 execute_process(
     COMMAND
+        ${MBEDTLS_PYTHON_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/../tests/scripts/generate_psa_tests.py
         --list-for-cmake
         --directory suites