tty: serial: xilinx_uartps: Fix documentation for cdns_uart_clk_notifier_cb()

tty: serial: xilinx_uartps: Fix documentation for cdns_uart_clk_notifier_cb()

Fixes the following W=1 kernel build warning(s):

 drivers/tty/serial/xilinx_uartps.c:496: warning: expecting prototype for cdns_uart_clk_notitifer_cb(). Prototype was for cdns_uart_clk_notifier_cb() instead

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210520121906.3468725-12-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>