selftests: devlink: fix the fd redirect in dummy_reporter_test

$number + > bash means redirect FD $number, e.g. commonly
used 2> redirects stderr (fd 2). The test uses 8192> to
write the number 8192 to a file, this results in:

  ./devlink.sh: line 499: 8192: Bad file descriptor

Oddly the test also papers over this issue by checking
for failure (expecting an error rather than success)
so it passes, anyway.

Fixes: ff18176a ("selftests: Add a test of large binary to devlink health test")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/netdevsim/devlink.sh

@@ -496,8 +496,8 @@ dummy_reporter_test()
 
 	check_reporter_info dummy healthy 3 3 10 true
 
-	echo 8192> $DEBUGFS_DIR/health/binary_len
-	check_fail $? "Failed set dummy reporter binary len to 8192"
+	echo 8192 > $DEBUGFS_DIR/health/binary_len
+	check_err $? "Failed set dummy reporter binary len to 8192"
 
 	local dump=$(devlink health dump show $DL_HANDLE reporter dummy -j)
 	check_err $? "Failed show dump of dummy reporter"