[SPARC]: Implement fb_is_primary_device().

Signed-off-by: David S. Miller <davem@davemloft.net>

include/asm-sparc/fb.h

@@ -1,11 +1,20 @@
 #ifndef _ASM_FB_H_
 #define _ASM_FB_H_
 #include <linux/fb.h>
+#include <asm/prom.h>
 
 #define fb_pgprotect(...) do {} while (0)
 
 static inline int fb_is_primary_device(struct fb_info *info)
 {
+	struct device *dev = info->device;
+	struct device_node *node;
+
+	node = dev->archdata.prom_node;
+	if (node &&
+	    node == of_console_device)
+		return 1;
+
 	return 0;
 }