Cleanup PSA ifdefs for CBC block mode

Try to make these definitions clearer given the complexity of the
mapping between the PSA config options and the MBEDTLS ones.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/include/mbedtls/config_psa.h b/include/mbedtls/config_psa.h
index a12b52a..b085500 100644
--- a/include/mbedtls/config_psa.h
+++ b/include/mbedtls/config_psa.h
@@ -333,26 +333,20 @@
 
 #if defined(PSA_WANT_ALG_CBC_NO_PADDING) || defined(PSA_WANT_ALG_CBC_PKCS7)
 #define MBEDTLS_CIPHER_MODE_CBC
-#if defined(PSA_WANT_ALG_CBC_PKCS7)
-#define MBEDTLS_CIPHER_PADDING_PKCS7
-#endif /* PSA_WANT_ALG_CBC_PKCS7 */
 #endif /* PSA_WANT_ALG_CBC_NO_PADDING || PSA_WANT_ALG_CBC_PKCS7 */
 
 #if defined(PSA_WANT_ALG_CBC_NO_PADDING)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_CBC_NO_PADDING) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_AES) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_DES) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_CAMELLIA)
+    defined(PSA_HAVE_SOFT_BLOCK_CIPHER)
 #define MBEDTLS_PSA_BUILTIN_ALG_CBC_NO_PADDING 1
 #endif
 #endif /* PSA_WANT_ALG_CBC_NO_PADDING */
 
 #if defined(PSA_WANT_ALG_CBC_PKCS7)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_CBC_PKCS7) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_AES) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_DES) || \
-    defined(PSA_HAVE_SOFT_KEY_TYPE_CAMELLIA)
+    defined(PSA_HAVE_SOFT_BLOCK_CIPHER)
 #define MBEDTLS_PSA_BUILTIN_ALG_CBC_PKCS7 1
+#define MBEDTLS_CIPHER_PADDING_PKCS7
 #endif
 #endif /* PSA_WANT_ALG_CBC_PKCS7 */