drm/msm: Remove local fbdev emulation Kconfig option

DRM_MSM_FBDEV config is used to enable/disable fbdev emulation for the
msm kms driver.

Replace this with the top level DRM_FBDEV_EMULATION config option where
applicable. This also prevents build breaks caused by undefined
drm_fb_helper_* functions when legacy fbdev support was disabled.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index 0a543eb..1c90290 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -50,7 +50,7 @@
 	msm_rd.o \
 	msm_ringbuffer.o
 
-msm-$(CONFIG_DRM_MSM_FBDEV) += msm_fbdev.o
+msm-$(CONFIG_DRM_FBDEV_EMULATION) += msm_fbdev.o
 msm-$(CONFIG_COMMON_CLK) += mdp/mdp4/mdp4_lvds_pll.o
 
 msm-$(CONFIG_DRM_MSM_DSI) += dsi/dsi.o \