serial: 8250-of: Fix style issues in 8250_of.c

This patch resolves the warning "sizeof *port should be sizeof(*port)"
detected by checkpatch.pl.

Signed-off-by: jempty.liang <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/8250/8250_of.c

···
 	u32 spd;
 	int ret;
 
-	memset(port, 0, sizeof *port);
+	memset(port, 0, sizeof(*port));
 
 	pm_runtime_enable(&ofdev->dev);
 	pm_runtime_get_sync(&ofdev->dev);