mmc: at91sam9x5: support to save environment in mmc

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Andreas Bießmann <andreas.devel@googlemail.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/boards.cfg b/boards.cfg
index 7ae663c..b8a238a 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -98,6 +98,7 @@
 at91sam9rlek_nandflash       arm         arm926ejs   at91sam9rlek        atmel          at91        at91sam9rlek:AT91SAM9RL,SYS_USE_NANDFLASH
 at91sam9x5ek_nandflash       arm         arm926ejs   at91sam9x5ek        atmel          at91        at91sam9x5ek:AT91SAM9X5,SYS_USE_NANDFLASH
 at91sam9x5ek_spiflash        arm         arm926ejs   at91sam9x5ek        atmel          at91        at91sam9x5ek:AT91SAM9X5,SYS_USE_SPIFLASH
+at91sam9x5ek_mmc             arm         arm926ejs   at91sam9x5ek        atmel          at91        at91sam9x5ek:AT91SAM9X5,SYS_USE_MMC
 at91sam9xeek_dataflash_cs0   arm         arm926ejs   at91sam9260ek       atmel          at91        at91sam9260ek:AT91SAM9XE,SYS_USE_DATAFLASH_CS0
 at91sam9xeek_dataflash_cs1   arm         arm926ejs   at91sam9260ek       atmel          at91        at91sam9260ek:AT91SAM9XE,SYS_USE_DATAFLASH_CS1
 at91sam9xeek_nandflash       arm         arm926ejs   at91sam9260ek       atmel          at91        at91sam9260ek:AT91SAM9XE,SYS_USE_NANDFLASH