[PATCH v2 -next] scsi: qla2xxx: Fix build error implicit-function-declaration

[Ren Zhijie <renzhijie2@xxxxxxxxxx>]

If CONFIG_TRACING is not set,
make ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-,
will be failed, like this:

drivers/scsi/qla2xxx/qla_os.c: In function ‘qla_trace_init’:
drivers/scsi/qla2xxx/qla_os.c:2854:18: error: implicit declaration of function ‘trace_array_get_by_name’; did you mean ‘trace_array_set_clr_event’? [-Werror=implicit-function-declaration]
  qla_trc_array = trace_array_get_by_name("qla2xxx");
                  ^~~~~~~~~~~~~~~~~~~~~~~
                  trace_array_set_clr_event
drivers/scsi/qla2xxx/qla_os.c:2854:16: error: assignment makes pointer from integer without a cast [-Werror=int-conversion]
  qla_trc_array = trace_array_get_by_name("qla2xxx");
                ^
drivers/scsi/qla2xxx/qla_os.c: In function ‘qla_trace_uninit’:
drivers/scsi/qla2xxx/qla_os.c:2869:2: error: implicit declaration of function ‘trace_array_put’; did you mean ‘trace_seq_putc’? [-Werror=implicit-function-declaration]
  trace_array_put(qla_trc_array);
  ^~~~~~~~~~~~~~~
  trace_seq_putc
cc1: all warnings being treated as errors

To fix this error, wrap up all the relevant code with CONFIG_TRACING.

Fixes: 8bfc149ba24c ("scsi: qla2xxx: Enhance driver tracing with separate tunable and more")
Signed-off-by: Ren Zhijie <renzhijie2@xxxxxxxxxx>
---
Changes in v2:
 - warp the definition statement of qla_trace_init() and qla_trace_uninit() with CONFIG_TRACING.
---
 drivers/scsi/qla2xxx/qla_os.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 2c85f3cce726..f64063e56f3d 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -37,7 +37,9 @@ static int apidev_major;
  */
 struct kmem_cache *srb_cachep;
 
+#ifdef CONFIG_TRACING
 static struct trace_array *qla_trc_array;
+#endif
 
 int ql2xfulldump_on_mpifail;
 module_param(ql2xfulldump_on_mpifail, int, S_IRUGO | S_IWUSR);
@@ -2851,6 +2853,7 @@ static void qla2x00_iocb_work_fn(struct work_struct *work)
 static void
 qla_trace_init(void)
 {
+#ifdef CONFIG_TRACING
 	qla_trc_array = trace_array_get_by_name("qla2xxx");
 	if (!qla_trc_array) {
 		ql_log(ql_log_fatal, NULL, 0x0001,
@@ -2859,14 +2862,17 @@ qla_trace_init(void)
 	}
 
 	QLA_TRACE_ENABLE(qla_trc_array);
+#endif
 }
 
 static void
 qla_trace_uninit(void)
 {
+#ifdef CONFIG_TRACING
 	if (!qla_trc_array)
 		return;
 	trace_array_put(qla_trc_array);
+#endif
 }
 
 /*
-- 
2.17.1