linux: Turn off FB_OF

This is unused on powernv machines.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/linux/skiroot_defconfig b/openpower/configs/linux/skiroot_defconfig
index 751a4fd..f05f16d 100644
--- a/openpower/configs/linux/skiroot_defconfig
+++ b/openpower/configs/linux/skiroot_defconfig
@@ -218,7 +218,6 @@
 CONFIG_DRM_AST=m
 CONFIG_FB=y
 CONFIG_FIRMWARE_EDID=y
-CONFIG_FB_OF=y
 # CONFIG_VGA_CONSOLE is not set
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_LOGO=y