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/at91sam9261ek.h b/include/configs/at91sam9261ek.h
index 3d108ab..f86698f 100644
--- a/include/configs/at91sam9261ek.h
+++ b/include/configs/at91sam9261ek.h
@@ -181,7 +181,7 @@
 #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"
 
 #elif CONFIG_SYS_USE_DATAFLASH_CS3
@@ -195,7 +195,7 @@
 #define CONFIG_BOOTCOMMAND	"cp.b 0xD0042000 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 */
@@ -208,7 +208,7 @@
 #define CONFIG_BOOTCOMMAND	"nand read 0x22000000 0xA0000 0x200000; bootm"
 #define CONFIG_BOOTARGS		"console=ttyS0,115200 "			\
 				"root=/dev/mtdblock5 "			\
-				"mtdparts=at91_nand:128k(bootstrap)ro,"	\
+				"mtdparts=atmel_nand:128k(bootstrap)ro,"	\
 				"256k(uboot)ro,128k(env1)ro,"		\
 				"128k(env2)ro,2M(linux),-(root) "	\
 				"rw rootfstype=jffs2"