ARM: OMAP: Fix compile for hsmmc boards

It can't be static, it gets from board-*.c files as
noted by Paul Walmsley.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/devices.c

@@ -343,8 +343,7 @@ void omap_set_mmc_info(int host, const struct omap_mmc_platform_data *info)
 }
 
 #else
-static void omap_set_mmc_info(int host,
-	const struct omap_mmc_platform_data *info) {}
+void omap_set_mmc_info(int host, const struct omap_mmc_platform_data *info) {}
 static inline void omap_init_mmc(void) {}
 #endif