Hide the video drivers for onboard graphics found in early PCI PowerMacs in
Apple G5 config files.

drivers/built-in.o: In function `.platinumfb_probe':
platinumfb.c:(.text+0x377a0): undefined reference to `.nvram_read_byte'
platinumfb.c:(.text+0x37830): undefined reference to `.nvram_read_byte'
drivers/built-in.o: In function `.control_init':
controlfb.c:(.init.text+0x1938): undefined reference to `.nvram_read_byte'
controlfb.c:(.init.text+0x1968): undefined reference to `.nvram_read_byte'
drivers/built-in.o: In function `.valkyriefb_init':
(.init.text+0x2300): undefined reference to `.nvram_read_byte'
drivers/built-in.o:(.init.text+0x239c): more undefined references to `.nvram_read_byte' follow

Signed-off-by: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>