ARM: davinci_all_defconfig: enable GPIO backlight

DA850 EVM has been converted to use GPIO backlight device
for display backlight GPIO control.

Enable the GPIO backlight module in davinci_all_defconfig
to keep backlight support working.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
[nsekhar@ti.com: edits to commit message for context]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/configs/davinci_all_defconfig

@@ -167,6 +167,7 @@ CONFIG_FB=y
 CONFIG_FIRMWARE_EDID=y
 CONFIG_FB_DA8XX=y
 CONFIG_BACKLIGHT_PWM=m
+CONFIG_BACKLIGHT_GPIO=m
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_LOGO=y
 CONFIG_SOUND=m