Define always psa_key_id_t as defined in PSA crypto spec

Define always psa_key_id_t as defined in the PSA
Cryptography API specification independently of
whether the MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER
configuration file is set or not.

As a consequence, get rid of `psa_app_key_id_t` that is
not needed anymore.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto_se.h b/library/psa_crypto_se.h
index 258c211..5691738 100644
--- a/library/psa_crypto_se.h
+++ b/library/psa_crypto_se.h
@@ -51,7 +51,7 @@
  * actually not used since it corresponds to #PSA_KEY_LOCATION_LOCAL_STORAGE
  * which doesn't have a driver.
  */
-#define PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE ( (psa_app_key_id_t) 0xfffffe00 )
+#define PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE ( (psa_key_id_t) 0xfffffe00 )
 
 /** The maximum number of registered secure element driver locations. */
 #define PSA_MAX_SE_DRIVERS 4