drivers/video/backlight/Kconfig: fix typo "MACH_SAM9...EK" three times

Fix three typos (originally) introduced by commit a9a84c3
("atmel_lcdfb: backlight control").

Two of these typos were introduced in v2.6.25.  (The third was
introduced in 915190f ("[ARM] 5614/1: at91: atmel_lcdfb: add
at91sam9g10 support to atmel LCD driver")).  Checking these commits
reveals that the default value of 'y' has never been set automatically
in all releases since v2.6.25! Perhaps this line might as well be
dropped.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/Kconfig

@@ -161,7 +161,7 @@ if BACKLIGHT_CLASS_DEVICE
 config BACKLIGHT_ATMEL_LCDC
 	bool "Atmel LCDC Contrast-as-Backlight control"
 	depends on FB_ATMEL
-	default y if MACH_SAM9261EK || MACH_SAM9G10EK || MACH_SAM9263EK
+	default y if MACH_AT91SAM9261EK || MACH_AT91SAM9G10EK || MACH_AT91SAM9263EK
 	help
 	  This provides a backlight control internal to the Atmel LCDC
 	  driver.  If the LCD "contrast control" on your board is wired