RDMA/hns: Fix build error of hns_roce_trace

Add include path to find hns_roce_trace.h to fix the following
build error:

In file included from drivers/infiniband/hw/hns/hns_roce_trace.h:213,
                 from drivers/infiniband/hw/hns/hns_roce_hw_v2.c:53:
./include/trace/define_trace.h:110:42: fatal error: ./hns_roce_trace.h: No such file or directory
  110 | #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
      |                                          ^
compilation terminated.

Fixes: 02007e3 ("RDMA/hns: Add trace for flush CQE")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Closes: https://lore.kernel.org/linux-next/b7dd4dda-37d8-47e4-8d78-b6585be21cfd@paulmck-laptop/T/#t
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20250507033903.2879433-1-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: Junxian Huang

drivers/infiniband/hw/hns/Makefile

@@ -4,6 +4,7 @@
 #
 
 ccflags-y :=  -I $(srctree)/drivers/net/ethernet/hisilicon/hns3
+ccflags-y +=  -I $(src)
 
 hns-roce-hw-v2-objs := hns_roce_main.o hns_roce_cmd.o hns_roce_pd.o \
 	hns_roce_ah.o hns_roce_hem.o hns_roce_mr.o hns_roce_qp.o \