Change error description

1. Change error description to a clearer one.
2. Change value in the error codes ranges description.
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index c9a8250..6c69a9b 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -80,7 +80,7 @@
  * CHACHA20  3                  0x0051-0x0055
  * POLY1305  3                  0x0057-0x005B
  * CHACHAPOLY 2 0x0054-0x0056
- * PLATFORM  1  0x0080-0x0080
+ * PLATFORM  1  0x0070-0x0070
  *
  * High-level module nr (3 bits - 0x0...-0x7...)
  * Name      ID  Nr of Errors