arm: mach-omap1: board-innovator: make innovator_mmc_init() static

Eliminates the following sparse warning:

	arch/arm/mach-omap1/board-innovator.c:368:13: warning: symbol 'innovator_mmc_init' was not declared. Should it be static?

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