arch/sim: fix undefined reference to `usrsock_event_callback'

/usr/bin/ld: sim_hostusrsock.o: in function `host_usrsock_loop':
arch/sim/src/sim/posix/sim_hostusrsock.c:514: undefined reference to `usrsock_event_callback'

Signed-off-by: chao an <anchao@xiaomi.com>

arch/sim/src/Makefile

@@ -40,6 +40,9 @@ NUTTX = $(call CONVERT_PATH,$(TOPDIR)$(DELIM)nuttx$(EXEEXT))
 
 LINKOBJS = sim_head$(OBJEXT)
 REQUIREDOBJS = $(LINKOBJS) sim_doirq$(OBJEXT)
+ifeq ($(CONFIG_SIM_NETUSRSOCK),y)
+  REQUIREDOBJS += sim_usrsock$(OBJEXT)
+endif
 
 ifeq ($(CONFIG_HOST_X86_64),y)
 ifeq ($(CONFIG_SIM_M32),y)