[nrf fromlist] samples: net: zperf: Fine tune memory to align zero-copy

Now that nRF70 by default uses zero-copy fine-tune the configuration to
get optimal memory while getting peak throughputs.

Upstream PR #: 87655

Signed-off-by: Chaitanya Tata <[email protected]>

Author: krish2718

samples/net/zperf/boards/nrf7002dk_nrf5340_cpuapp.conf

@@ -1,11 +1,11 @@
 # Optimized networking settings for performance
 CONFIG_NET_PKT_RX_COUNT=28
-CONFIG_NET_PKT_TX_COUNT=27
+CONFIG_NET_PKT_TX_COUNT=28
 CONFIG_NET_BUF_RX_COUNT=28
-CONFIG_NET_BUF_TX_COUNT=54
-# reduces driver heap usage
+CONFIG_NET_BUF_TX_COUNT=28
 CONFIG_NRF70_RX_NUM_BUFS=16
-CONFIG_NRF_WIFI_DATA_HEAP_SIZE=50000
+CONFIG_NRF_WIFI_DATA_HEAP_SIZE=30000
+CONFIG_NET_PKT_BUF_TX_DATA_POOL_SIZE=20000
 CONFIG_NRF70_MAX_TX_AGGREGATION=4
 CONFIG_NRF70_QSPI_LOW_POWER=n