arm: mach-omap1: board-voiceblue: add missing include

Eliminates the following sparse warnings:

	arch/arm/mach-omap1/board-voiceblue.c:253:6: warning: symbol 'voiceblue_wdt_enable' was not declared. Should it be static?
	arch/arm/mach-omap1/board-voiceblue.c:261:6: warning: symbol 'voiceblue_wdt_disable' was not declared. Should it be static?
	arch/arm/mach-omap1/board-voiceblue.c:269:6: warning: symbol 'voiceblue_wdt_ping' was not declared. Should it be static?
	arch/arm/mach-omap1/board-voiceblue.c:278:6: warning: symbol 'voiceblue_reset' was not declared. Should it be static?

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Tony Lindgren <tony@atomide.com>