samples: wifi: sta: Reduce RAM usage

In few experiments, it was found that we only 75000 heap for driver,
this reduced 15000 RAM.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>

samples/wifi/sta/prj.conf

@@ -28,12 +28,13 @@ CONFIG_NET_DHCPV4=y
 
 CONFIG_NET_PKT_RX_COUNT=16
 CONFIG_NET_PKT_TX_COUNT=16
+CONFIG_NRF70_RX_NUM_BUFS=16
 
 # Below section is the primary contributor to SRAM and is currently
 # tuned for performance, but this will be revisited in the future.
 CONFIG_NET_BUF_RX_COUNT=16
 CONFIG_NET_BUF_TX_COUNT=32
-CONFIG_HEAP_MEM_POOL_SIZE=120000
+CONFIG_HEAP_MEM_POOL_SIZE=105000
 CONFIG_HEAP_MEM_POOL_IGNORE_MIN=y
 CONFIG_NET_TC_TX_COUNT=1