Automatically enable PK_PARSE for RSA in PSA

PSA crypto currently needs MBEDTLS_PK_PARSE_C to parse RSA keys to do almost
anything with them (import, get attributes, export public from private, any
cryptographic operations). Force it on, for symmetry with what we're doing
for MBEDTLS_PK_WRITE_C. Fixes #6409.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index fa41604..30ab9ba 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -1572,11 +1572,11 @@
   scripts/config.py unset MBEDTLS_PEM_WRITE_C
   scripts/config.py unset MBEDTLS_PKCS12_C
   scripts/config.py unset MBEDTLS_PKCS5_C
-  # MBEDTLS_PK_WRITE_C is actually currently needed for RSA key export,
-  # but build_info.h will reenable it.
+  # MBEDTLS_PK_PARSE_C and MBEDTLS_PK_WRITE_C are actually currently needed
+  # in PSA code to work with RSA keys. We don't require users to set those:
+  # they will be reenabled in build_info.h.
+  scripts/config.py unset MBEDTLS_PK_PARSE_C
   scripts/config.py unset MBEDTLS_PK_WRITE_C
-  # At this time, we can't unset MBEDTLS_PK_PARSE_C, because it's needed
-  # for RSA in PSA (see https://github.com/Mbed-TLS/mbedtls/issues/6408).
   make CFLAGS='-O1 -Werror' all test
   are_empty_libraries library/libmbedx509.* library/libmbedtls.*
 }