kernel: add missing DRM symbols to generic config

Several new DRM symbols that were introduced after 4.9 are missing in
the generic config for 4.14, so add them.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

target/linux/generic/config-4.14

@@ -1143,6 +1143,7 @@ CONFIG_DQL=y
 # CONFIG_DRM_DEBUG_MM_SELFTEST is not set
 # CONFIG_DRM_DP_AUX_CHARDEV is not set
 # CONFIG_DRM_DUMB_VGA_DAC is not set
+# CONFIG_DRM_DW_HDMI_CEC is not set
 # CONFIG_DRM_ETNAVIV is not set
 # CONFIG_DRM_EXYNOS is not set
 # CONFIG_DRM_FBDEV_EMULATION is not set
@@ -1156,8 +1157,11 @@ CONFIG_DQL=y
 # CONFIG_DRM_I2C_SIL164 is not set
 # CONFIG_DRM_LEGACY is not set
 # CONFIG_DRM_LOAD_EDID_FIRMWARE is not set
+# CONFIG_DRM_LVDS_ENCODER is not set
 # CONFIG_DRM_MALI_DISPLAY is not set
+# CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW is not set
 # CONFIG_DRM_MGAG200 is not set
+# CONFIG_DRM_MXSFB is not set
 # CONFIG_DRM_NOUVEAU is not set
 # CONFIG_DRM_NXP_PTN3460 is not set
 # CONFIG_DRM_OMAP is not set
@@ -1170,12 +1174,16 @@ CONFIG_DQL=y
 # CONFIG_DRM_PANEL_SHARP_LQ101R1SX01 is not set
 # CONFIG_DRM_PANEL_SHARP_LS043T1LE01 is not set
 # CONFIG_DRM_PARADE_PS8622 is not set
+# CONFIG_DRM_PL111 is not set
 # CONFIG_DRM_QXL is not set
 # CONFIG_DRM_RADEON is not set
+# CONFIG_DRM_RCAR_DW_HDMI is not set
 # CONFIG_DRM_SII902X is not set
+# CONFIG_DRM_SIL_SII8620 is not set
 # CONFIG_DRM_STI is not set
 # CONFIG_DRM_TILCDC is not set
 # CONFIG_DRM_TINYDRM is not set
+# CONFIG_DRM_TI_TFP410 is not set
 # CONFIG_DRM_TOSHIBA_TC358767 is not set
 # CONFIG_DRM_UDL is not set
 # CONFIG_DRM_VBOXVIDEO is not set