IMA: Add log statements for failure conditions

process_buffer_measurement() does not have log messages for failure
conditions.

This change adds a log statement in the above function.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

security/integrity/ima/ima_main.c

@@ -757,6 +757,9 @@ void process_buffer_measurement(const void *buf, int size,
 		ima_free_template_entry(entry);
 
 out:
+	if (ret < 0)
+		pr_devel("%s: failed, result: %d\n", __func__, ret);
+
 	return;
 }