The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)
In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-22-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  * Copyright (C) 2014 Carlo Caione <carlo@caione.org>
  */
 
-#if defined(CONFIG_SERIAL_MESON_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
-#define SUPPORT_SYSRQ
-#endif
-
 #include <linux/clk.h>
 #include <linux/console.h>
 #include <linux/delay.h>
        port->mapsize = resource_size(res_mem);
        port->irq = res_irq->start;
        port->flags = UPF_BOOT_AUTOCONF | UPF_LOW_LATENCY;
+       port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MESON_CONSOLE);
        port->dev = &pdev->dev;
        port->line = pdev->id;
        port->type = PORT_MESON;