Documentation: serial: link uart_ops properly

The syntax to reference a struct in text is "struct XY". So reference
uart_ops properly, so that hyperlinks work.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220728061056.20799-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/serial/driver.rst

@@ -39,7 +39,7 @@ Locking
 
 It is the responsibility of the low level hardware driver to perform the
 necessary locking using port->lock.  There are some exceptions (which
-are described in the uart_ops listing below.)
+are described in the struct uart_ops listing below.)
 
 There are two locks.  A per-port spinlock, and an overall semaphore.