Enable Mirror ACL for cisco-8000 asic type (sonic-net#2059)

What I did

Enable ACL mirror capabilities for platform type CISCO_8000_PLATFORM_SUBSTRING

Why I did it
Enable Mirror ACL for Cisco Silicon Platforms.

Signed-off-by: Venkat Garigipati <venkatg@cisco.com>

orchagent/aclorch.cpp

@@ -2646,6 +2646,7 @@ void AclOrch::init(vector<TableConnector>& connectors, PortsOrch *portOrch, Mirr
     // purposes.
     string platform = getenv("platform") ? getenv("platform") : "";
     if (platform == BRCM_PLATFORM_SUBSTRING ||
+            platform == CISCO_8000_PLATFORM_SUBSTRING ||
             platform == MLNX_PLATFORM_SUBSTRING ||
             platform == BFN_PLATFORM_SUBSTRING  ||
             platform == MRVL_PLATFORM_SUBSTRING ||
@@ -2676,6 +2677,7 @@ void AclOrch::init(vector<TableConnector>& connectors, PortsOrch *portOrch, Mirr
 
     // In Mellanox platform, V4 and V6 rules are stored in different tables
     if (platform == MLNX_PLATFORM_SUBSTRING ||
+        platform == CISCO_8000_PLATFORM_SUBSTRING ||
         platform == MRVL_PLATFORM_SUBSTRING)
     {
         m_isCombinedMirrorV6Table = false;