defconfig: display: rename overlay writeback config flag

CONFIG_FB_MSM_OVERLAY_WRITEBACK is changed to
CONFIG_FB_MSM_OVERLAY0_WRITEBACK to be more specific for msm8x60 and
msm8960. Later overlay1 writeback flag will be added.

Change-Id: I5ecbcf9ec70c3911de94555ad80dd8509c7ffe22
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
diff --git a/arch/arm/configs/msm8960_defconfig b/arch/arm/configs/msm8960_defconfig
index f1cd7fd..ee31efc 100644
--- a/arch/arm/configs/msm8960_defconfig
+++ b/arch/arm/configs/msm8960_defconfig
@@ -304,7 +304,7 @@
 CONFIG_FB_MSM_TRIPLE_BUFFER=y
 CONFIG_FB_MSM_MDP40=y
 CONFIG_FB_MSM_OVERLAY=y
-CONFIG_FB_MSM_OVERLAY_WRITEBACK=y
+CONFIG_FB_MSM_OVERLAY0_WRITEBACK=y
 CONFIG_FB_MSM_MIPI_PANEL_DETECT=y
 CONFIG_FB_MSM_HDMI_MSM_PANEL=y
 CONFIG_BACKLIGHT_LCD_SUPPORT=y