OMAP2plus: Fix static function warnings

This patch fixes sparse warnings due non declarations of static functions.

arch/arm/mach-omap2/timer-gp.c:115:12: warning: symbol 'omap2_gp_clockevent_set_gptimer' was not declared. Should it be static?
arch/arm/mach-omap2/powerdomain.c:993:5: warning: symbol 'pwrdm_set_lowpwrstchange' was not declared. Should it be static?
arch/arm/mach-omap2/board-flash.c:141:8: warning: symbol 'board_nand_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-n8x0.c:416:6: warning: symbol 'n8x0_mmc_slot1_cover_handler' was not declared. Should it be static?
arch/arm/mach-omap2/board-n8x0.c:544:13: warning: symbol 'n8x0_mmc_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-rx51-peripherals.c:902:13: warning: symbol 'rx51_peripherals_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-rx51-video.c:107:13: warning: symbol 'rx51_video_mem_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-zoom-debugboard.c:155:12: warning: symbol 'zoom_debugboard_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-zoom-peripherals.c:280:13: warning: symbol 'zoom_peripherals_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-igep0020.c:110:13: warning: symbol 'igep2_flash_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-am3517evm.c:109:6: warning: symbol 'am3517_evm_ethernet_init' was not declared. Should it be static?
drivers/mtd/onenand/omap2.c:577:5: warning: symbol 'omap2_onenand_rephase' was not declared. Should it be static?

Signed-off-by: Manjunath Kondaiah G <manjugk@ti.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>