video: fbdev: arcfb: add COMPILE_TEST support

Add COMPILE_TEST support to arcfb driver for better compile
testing coverage.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/acf2cc2e-614d-f0fb-ce40-cee62bfcde4c@samsung.com

drivers/video/fbdev/Kconfig

@@ -435,7 +435,7 @@ config FB_FM2
 
 config FB_ARC
 	tristate "Arc Monochrome LCD board support"
-	depends on FB && X86
+	depends on FB && (X86 || COMPILE_TEST)
 	select FB_SYS_FILLRECT
 	select FB_SYS_COPYAREA
 	select FB_SYS_IMAGEBLIT