fbdev: make get_fb_unmapped_area depends of !MMU

Even if CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA flag is selected
do not compile and use get_fb_unmapped_area() if CONFIG_MMU is
also set. This will avoid mmap errors when compiling multi
architectures at same time.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Yannick Fertre <yannick.fertre@st.com>
Cc: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/core/fbmem.c

@@ -1492,7 +1492,7 @@ __releases(&info->lock)
 	return 0;
 }
 
-#ifdef CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA
+#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
 unsigned long get_fb_unmapped_area(struct file *filp,
 				   unsigned long addr, unsigned long len,
 				   unsigned long pgoff, unsigned long flags)
@@ -1519,7 +1519,8 @@ static const struct file_operations fb_fops = {
 	.open =		fb_open,
 	.release =	fb_release,
 #if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
-    defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA)
+	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
+	 !defined(CONFIG_MMU))
 	.get_unmapped_area = get_fb_unmapped_area,
 #endif
 #ifdef CONFIG_FB_DEFERRED_IO