[BT-6710]change type access di1, di2

docs/bt6710/BT6710.MIB

@@ -47,7 +47,7 @@ IMPORTS
     
     di1 OBJECT-TYPE
     SYNTAX  OCTET STRING
-    MAX-ACCESS  read-write
+    MAX-ACCESS  read-only
     STATUS  current
     DESCRIPTION
     "State of dry input 1
@@ -57,7 +57,7 @@ IMPORTS
     
     di2 OBJECT-TYPE
     SYNTAX  OCTET STRING
-    MAX-ACCESS  read-write
+    MAX-ACCESS  read-only
     STATUS  current
     DESCRIPTION
     "State of dry input 2