Update lower_bound of ipv6_prefix_length to 0

The hypervisor supports the lower bound value of the IPv6 prefix length to be 0, however on the bmc it is limited at 1. Hence in PLDM it returns an error when it tries to assign the unsupported value 0.

This change updates the lower_bound value of ipv6_prefix_length to 0 from 1.

Tested by:

Step 1:
Patch an IPv6 address on the ethernet interface with prefix length 0 using the redfish patch command

PATCH -D'{"IPv6StaticAddresses": [{"Address": "2002:903:15f:325:123:123:123:124","PrefixLength": 0}]}' https://${bmc}/redfish/v1/Systems/hypervisor/EthernetInterfaces/eth1

Result:
Doesn't throw any error. Command is executed successfully.

Step 2:
Run a redfish GET command on the same ethernet interface and check the IPv6 address section of the IP address configured above.

Result:
Prefix length of the IP address is 0
GET -D patch1.txt https://${bmc}/redfish/v1/Systems/hypervisor/EthernetInterfaces/eth1
{
  ....
  ....
  "IPv6AddressPolicyTable": [],
  "IPv6Addresses": [
    {
      "Address": "2002:903:15f:325:123:123:123:124",
      "AddressOrigin": "Static",
      "PrefixLength": 0
    }
  ],
  ....
  ....
  }

Change-Id: I3f1c76ea22e2856c22dae7a3d7d1fcbc9b07d446
Signed-off-by: Jishnu CM <jishnunambiarcm@duck.com>
diff --git a/oem/ibm/configurations/bios/integer_attrs.json b/oem/ibm/configurations/bios/integer_attrs.json
index e415d4e..d77a959 100644
--- a/oem/ibm/configurations/bios/integer_attrs.json
+++ b/oem/ibm/configurations/bios/integer_attrs.json
@@ -20,7 +20,7 @@
         },
         {
             "attribute_name": "vmi_if0_ipv6_prefix_length",
-            "lower_bound": 1,
+            "lower_bound": 0,
             "upper_bound": 128,
             "scalar_increment": 1,
             "default_value": 128,
@@ -29,7 +29,7 @@
         },
         {
             "attribute_name": "vmi_if1_ipv6_prefix_length",
-            "lower_bound": 1,
+            "lower_bound": 0,
             "upper_bound": 128,
             "scalar_increment": 1,
             "default_value": 128,