Add board_mmc_init(...) function for init mmc1 only

Since B&R boards uses only MMC-Controller #1, it only
wastes time if we initialize #0 first to see that there is nothing.

Cc: <trini@ti.com>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: Hannes Petermaier <oe5hpm@oevsv.at>
diff --git a/include/configs/kwb.h b/include/configs/kwb.h
index 0f631c0..0860434 100644
--- a/include/configs/kwb.h
+++ b/include/configs/kwb.h
@@ -109,7 +109,7 @@
 
 #undef CONFIG_ENV_IS_NOWHERE
 #define CONFIG_ENV_IS_IN_MMC
-#define CONFIG_SYS_MMC_ENV_DEV		1
+#define CONFIG_SYS_MMC_ENV_DEV		0
 #define CONFIG_SYS_MMC_ENV_PART		2
 #define CONFIG_ENV_OFFSET		0x40000	/* TODO: Adresse definieren */
 #define CONFIG_ENV_OFFSET_REDUND	(CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE)