Add drivers/video/fbgen.o to export-objs.

fbgen.o was changed to explicitly export symbols but not added to
export-objs.

drivers/video/Makefile

@@ -15,7 +15,7 @@ export-objs    := fbmem.o fbcmap.o fbcon.o fbmon.o modedb.o \
 		  fbcon-iplan2p8.o fbcon-vga-planes.o fbcon-cfb16.o \
 		  fbcon-cfb2.o fbcon-cfb24.o fbcon-cfb32.o fbcon-cfb4.o \
 		  fbcon-cfb8.o fbcon-mac.o fbcon-mfb.o \
-		  cyber2000fb.o sa1100fb.o fbcon-hga.o
+		  cyber2000fb.o sa1100fb.o fbcon-hga.o fbgen.o
 
 # Each configuration option enables a list of files.