Linux: Suppress -Wordered-compare-function-pointers in tracepoint code

Clang points out that there is a comparison against -1, but we cannot
fix it because that is from the kernel headers, which we must support.
We can workaround this by using a pragma.

Sponsored-By: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Youzhong Yang <yyang@mathworks.com>
Signed-off-by: Richard Yao <richard.yao@klarasystems.com>
Closes openzfs#14738

include/os/linux/zfs/sys/trace_zil.h

@@ -152,6 +152,9 @@
  *     zilog_t *, ...,
  *     itx_t *, ...);
  */
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wordered-compare-function-pointers"
 /* BEGIN CSTYLED */
 DECLARE_EVENT_CLASS(zfs_zil_process_itx_class,
 	TP_PROTO(zilog_t *zilog, itx_t *itx),
@@ -169,6 +172,7 @@ DECLARE_EVENT_CLASS(zfs_zil_process_itx_class,
 	    ZILOG_TP_PRINTK_ARGS, ITX_TP_PRINTK_ARGS)
 );
 /* END CSTYLED */
+#pragma clang diagnostic pop
 
 #define	DEFINE_ZIL_PROCESS_ITX_EVENT(name) \
 DEFINE_EVENT(zfs_zil_process_itx_class, name, \