msm: defconfig: Enable writeback panel for wfd

For wifi display, the writeback panel is needed to capture the output of
mdp.  Setting this config enables the writeback panel.

Change-Id: I51006b74f63d286af6ca62bd95aa4fe2129f9fe4
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>
diff --git a/arch/arm/configs/msm8960_defconfig b/arch/arm/configs/msm8960_defconfig
index bac1123..bd92fe3 100644
--- a/arch/arm/configs/msm8960_defconfig
+++ b/arch/arm/configs/msm8960_defconfig
@@ -324,6 +324,7 @@
 CONFIG_FB_MSM_OVERLAY0_WRITEBACK=y
 CONFIG_FB_MSM_MIPI_PANEL_DETECT=y
 CONFIG_FB_MSM_HDMI_MSM_PANEL=y
+CONFIG_FB_MSM_WRITEBACK_MSM_PANEL=y
 CONFIG_BACKLIGHT_LCD_SUPPORT=y
 CONFIG_BACKLIGHT_CLASS_DEVICE=y
 CONFIG_SOUND=y