qcacld-3.0: Add feature flag for dp rx buffer cache

Add feature flag PEER_CACHE_RX_PKTS to support caching RX
buffers in dp.

Change-Id: Ie8cc7368568554c5320889cbb9ca8db4532cb03e
CRs-Fixed: 2442779

Kbuild

@@ -2683,6 +2683,7 @@ ccflags-y += -DFW_THERMAL_THROTTLE_SUPPORT
 endif
 
 cppflags-y += -DFEATURE_NBUFF_REPLENISH_TIMER
+cppflags-y += -DPEER_CACHE_RX_PKTS
 
 ccflags-$(CONFIG_HASTINGS_BT_WAR) += -DHASTINGS_BT_WAR