tegra2: Move tegra2_mmc_init() prototype to public header.

tegra2_mmc_init() is implemented by the Tegra2 MMC driver. Since most of
the Tegra2-based boards will need to call it, this commit exports it in
the new public asm/arch/mmc.h header file to prevent each board from
providing its own prototype.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/board/nvidia/harmony/harmony.c b/board/nvidia/harmony/harmony.c
index 3cbe820..d5e147d 100644
--- a/board/nvidia/harmony/harmony.c
+++ b/board/nvidia/harmony/harmony.c
@@ -25,11 +25,11 @@
 #include <asm/io.h>
 #include <asm/arch/tegra2.h>
 #include <asm/arch/pinmux.h>
+#include <asm/arch/mmc.h>
 #include <asm/gpio.h>
 #ifdef CONFIG_TEGRA2_MMC
 #include <mmc.h>
 #endif
-#include "../common/board.h"
 
 /*
  * Routine: gpio_config_uart