net: rename CONFIG_NET_LL_RX_POLL to CONFIG_NET_RX_BUSY_POLL

Eliezer renames several *ll_poll to *busy_poll, but forgets
CONFIG_NET_LL_RX_POLL, so in case of confusion, rename it too.

Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/Kconfig

@@ -244,7 +244,7 @@ config NETPRIO_CGROUP
 	  Cgroup subsystem for use in assigning processes to network priorities on
 	  a per-interface basis
 
-config NET_LL_RX_POLL
+config NET_RX_BUSY_POLL
 	boolean
 	default y