video/omap: fix build dependencies

Four of the LCD panel drivers depend on the backlight class,
so add the dependency in Kconfig.
Selecting the BACKLIGHT_CLASS_DEVICE symbol does not generally
work since it has other dependencies.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[tomi.valkeinen@ti.com: changed also N8x0 panel]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/displays/Kconfig

@@ -26,13 +26,15 @@ config PANEL_LGPHILIPS_LB035Q02
 config PANEL_SHARP_LS037V7DW01
         tristate "Sharp LS037V7DW01 LCD Panel"
         depends on OMAP2_DSS_DPI
-        select BACKLIGHT_CLASS_DEVICE
+        depends on BACKLIGHT_CLASS_DEVICE
         help
           LCD Panel used in TI's SDP3430 and EVM boards
 
 config PANEL_NEC_NL8048HL11_01B
 	tristate "NEC NL8048HL11-01B Panel"
 	depends on OMAP2_DSS_DPI
+	depends on SPI
+	depends on BACKLIGHT_CLASS_DEVICE
 	help
 		This NEC NL8048HL11-01B panel is TFT LCD
 		used in the Zoom2/3/3630 sdp boards.
@@ -47,6 +49,7 @@ config PANEL_PICODLP
 config PANEL_TAAL
         tristate "Taal DSI Panel"
         depends on OMAP2_DSS_DSI
+        depends on BACKLIGHT_CLASS_DEVICE
         help
           Taal DSI command mode panel from TPO.
 
@@ -59,14 +62,14 @@ config PANEL_TPO_TD043MTEA1
 config PANEL_ACX565AKM
 	tristate "ACX565AKM Panel"
 	depends on OMAP2_DSS_SDI && SPI
-	select BACKLIGHT_CLASS_DEVICE
+	depends on BACKLIGHT_CLASS_DEVICE
 	help
 	  This is the LCD panel used on Nokia N900
 
 config PANEL_N8X0
 	tristate "N8X0 Panel"
 	depends on OMAP2_DSS_RFBI && SPI
-	select BACKLIGHT_CLASS_DEVICE
+	depends on BACKLIGHT_CLASS_DEVICE
 	help
 	  This is the LCD panel used on Nokia N8x0
 endmenu