Update Nook Color machine 3284 to common Encore name

Machine database already updated:
http://www.arm.linux.org.uk/developer/machines/list.php?id=3284

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/tools/mach-types

@@ -910,7 +910,7 @@ omapl138_case_a3	MACH_OMAPL138_CASE_A3	OMAPL138_CASE_A3	3280
 uemd			MACH_UEMD		UEMD			3281
 ccwmx51mut		MACH_CCWMX51MUT		CCWMX51MUT		3282
 rockhopper		MACH_ROCKHOPPER		ROCKHOPPER		3283
-nookcolor		MACH_NOOKCOLOR		NOOKCOLOR		3284
+encore			MACH_ENCORE		ENCORE			3284
 hkdkc100		MACH_HKDKC100		HKDKC100		3285
 ts42xx			MACH_TS42XX		TS42XX			3286
 aebl			MACH_AEBL		AEBL			3287