meta-google: Add more customized options

Add options to disable always_available for gbmcbr and configure channel
15 to the right KCS bridge.

Tested:
- channel_access.json doesn't have gbmcbr
```
$ cat ./tmp/work/all-openbmc-linux/phosphor-ipmi-config/1.0/packages-split/phosphor-ipmi-config/usr/share/ipmi-providers/channel_config.json | jq '."15"'
{
  "name": "ipmi_kcs1",
  "is_valid": true,
  "active_sessions": 0,
  "channel_info": {
    "medium_type": "system-interface",
    "protocol_type": "kcs",
    "session_supported": "session-less",
    "is_ipmi": true
  }
}

// On ALWAYS_AVAILABLE_ON_GBMCBR_IPMI_CHANNEL=0
$ cat ./tmp/work/all-openbmc-linux/phosphor-ipmi-config/1.0/package/usr/share/ipmi-providers/channel_access.json
{
  "1": {
    "access_mode": "always_available",
    "user_auth_disabled": false,
    "per_msg_auth_disabled": false,
    "alerting_disabled": false,
    "priv_limit": "priv-admin"
  },
  "2": {
    "access_mode": "always_available",
    "user_auth_disabled": false,
    "per_msg_auth_disabled": false,
    "alerting_disabled": false,
    "priv_limit": "priv-admin"
  }
}
```


Change-Id: Idecd7337c29685faea2a648ab8246e79e1588ace
Signed-off-by: Willy Tu <wltu@google.com>

0 files changed, 0 insertions, 0 deletions