fbdev: au1100fb: Fix build on MIPS64

Fix an error reported by the kernel test robot:
 au1100fb.c: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'?

arch/mips/include/asm/addrspace.h defines KSEG1ADDR only for 32 bit
configurations. So provide its compile-test stub also for 64bit mips builds.

Fixes: 6f366e8 ("fbdev: au1100fb: Make driver compilable on non-mips platforms")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603042127.PT6LuKqi-lkp@intel.com/
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

Author: hdeller

drivers/video/fbdev/au1100fb.c

@@ -380,8 +380,12 @@ static struct au1100fb_panel known_lcd_panels[] =
 #define panel_is_color(panel) (panel->control_base & LCD_CONTROL_PC)
 #define panel_swap_rgb(panel) (panel->control_base & LCD_CONTROL_CCO)
 
-#if defined(CONFIG_COMPILE_TEST) && !defined(CONFIG_MIPS)
-/* This is only defined to be able to compile this driver on non-mips platforms */
+#if defined(CONFIG_COMPILE_TEST) && (!defined(CONFIG_MIPS) || defined(CONFIG_64BIT))
+/*
+ * KSEG1ADDR() is defined in arch/mips/include/asm/addrspace.h
+ * for 32 bit configurations. Provide a stub for compile testing
+ * on other platforms.
+ */
 #define KSEG1ADDR(x) (x)
 #endif