Update the mtd driver name in bootargs for at91-based boards

The name of the atmel nand driver in the kernel changed from at91_nand
to atmel_nand back in June 2008, but the at91-based boards config files
still refer to at91_nand. This patch updates them with the new name

Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
diff --git a/include/configs/at91sam9rlek.h b/include/configs/at91sam9rlek.h
index 9167304..b83266d 100644
--- a/include/configs/at91sam9rlek.h
+++ b/include/configs/at91sam9rlek.h
@@ -142,7 +142,7 @@
 #define CONFIG_BOOTCOMMAND	"cp.b 0xC0042000 0x22000000 0x210000; bootm"
 #define CONFIG_BOOTARGS		"console=ttyS0,115200 " \
 				"root=/dev/mtdblock0 " \
-				"mtdparts=at91_nand:-(root) "\
+				"mtdparts=atmel_nand:-(root) "\
 				"rw rootfstype=jffs2"
 
 #else /* CONFIG_SYS_USE_NANDFLASH */
@@ -155,7 +155,7 @@
 #define CONFIG_BOOTCOMMAND	"nand read 0x22000000 0xA0000 0x200000; bootm"
 #define CONFIG_BOOTARGS		"console=ttyS0,115200 " \
 				"root=/dev/mtdblock5 " \
-				"mtdparts=at91_nand:128k(bootstrap)ro,256k(uboot)ro,128k(env1)ro,128k(env2)ro,2M(linux),-(root) " \
+				"mtdparts=atmel_nand:128k(bootstrap)ro,256k(uboot)ro,128k(env1)ro,128k(env2)ro,2M(linux),-(root) " \
 				"rw rootfstype=jffs2"
 
 #endif