core: fix access conflict status in rpmb fs that panics TA

According to the GPD TEE Internal Core API specs, when creating
an existing persistent object without the overwrite flag, the OS
should return a TEE_ERROR_ACCESS_CONFLICT status.

This change fixes the RPMB FS layer. An effect of this correction
is that before this change, OS panicked TAs that requested such
forbidden object creation, as a TEE_ERROR_BAD_PARAMETERS return
value is considered by the API as an unexpected status.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (QEMU)

core/tee/tee_rpmb_fs.c

@@ -2251,7 +2251,7 @@ static  TEE_Result rpmb_fs_rename_internal(struct tee_pobj *old,
 	res = read_fat(fh_new, NULL);
 	if (res == TEE_SUCCESS) {
 		if (!overwrite) {
-			res = TEE_ERROR_BAD_PARAMETERS;
+			res = TEE_ERROR_ACCESS_CONFLICT;
 			goto out;
 		}