imx: nitrogen6x: Replace 'fatload' by 'load' command in env settings to be filesystem independent

nitrogen6x.h file defines CONFIG_CMD_FS_GENERIC, so we are able to use generic
'load' command instead of 'fatload'. It allows to use ext filesystem and keep
compatibilty with fat filesystem.

Signed-off-by: Guillaume GARDET <guillaume.gardet@free.fr>
Cc: Stefano Babic <sbabic@denx.de>
Acked-By: Eric Nelson <eric.nelson@boundarydevices.com>

include/configs/nitrogen6x.h

@@ -192,11 +192,11 @@
 	"mmcargs=setenv bootargs console=${console},${baudrate} " \
 		"root=${mmcroot}\0" \
 	"loadbootscript=" \
-		"fatload mmc ${mmcdev}:${mmcpart} ${loadaddr} ${script};\0" \
+		"load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${script};\0" \
 	"bootscript=echo Running bootscript from mmc ...; " \
 		"source\0" \
-	"loaduimage=fatload mmc ${mmcdev}:${mmcpart} ${loadaddr} ${uimage}\0" \
-	"loadfdt=fatload mmc ${mmcdev}:${mmcpart} ${fdt_addr} ${fdt_file}\0" \
+	"loaduimage=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${uimage}\0" \
+	"loadfdt=load mmc ${mmcdev}:${mmcpart} ${fdt_addr} ${fdt_file}\0" \
 	"mmcboot=echo Booting from mmc ...; " \
 		"run mmcargs; " \
 		"if test ${boot_fdt} = yes || test ${boot_fdt} = try; then " \