Enable SAI_SERDES_RX_REACH for TH6

Summary: title. Icetea and TahanSB needs to set the RxReach mode on backplane ports

Reviewed By: srikrishnagopu

Differential Revision: D89777436

fbshipit-source-id: 3a6325dfcd89c158cd0cecaea1a847952840a1c4

Author: Harshit Gulati

fboss/agent/hw/switch_asics/Tomahawk6Asic.cpp

@@ -110,6 +110,7 @@ bool Tomahawk6Asic::isSupported(Feature feature) const {
     case HwAsic::Feature::ARS_PORT_ATTRIBUTES:
     case HwAsic::Feature::ACL_SET_ECMP_HASH_ALGORITHM:
     case HwAsic::Feature::ARS:
+    case HwAsic::Feature::SAI_SERDES_RX_REACH:
       return true;
     // features not working well with bcmsim
     case HwAsic::Feature::MIRROR_PACKET_TRUNCATION:
@@ -225,7 +226,6 @@ bool Tomahawk6Asic::isSupported(Feature feature) const {
     case HwAsic::Feature::IN_DISCARDS_EXCLUDES_PFC:
     case HwAsic::Feature::INGRESS_BUFFER_POOL_SIZE_EXCLUDES_HEADROOM:
     case HwAsic::Feature::PORT_LEVEL_BUFFER_CONFIGURATION_SUPPORT:
-    case HwAsic::Feature::SAI_SERDES_RX_REACH:
     case HwAsic::Feature::ARS_FUTURE_PORT_LOAD:
       return false;
   }