mx28evk: We shouldn't hardcode a rootfs filesystem type

For a generic environment, we shouldn't have a fixed rootfs filesystem
so we drop it from env.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

include/configs/mx28evk.h

@@ -292,11 +292,9 @@
 	"console_mainline=ttyAMA0\0" \
 	"mmcdev=0\0" \
 	"mmcpart=2\0" \
-	"mmcroot=/dev/mmcblk0p3 rw\0" \
-	"mmcrootfstype=ext3 rootwait\0"	\
+	"mmcroot=/dev/mmcblk0p3 rw rootwait\0" \
 	"mmcargs=setenv bootargs console=${console_mainline},${baudrate} " \
-		"root=${mmcroot} " \
-		"rootfstype=${mmcrootfstype}\0"	\
+		"root=${mmcroot}\0" \
 	"loadbootscript="  \
 		"fatload mmc ${mmcdev}:${mmcpart} ${loadaddr} ${script};\0" \
 	"bootscript=echo Running bootscript from mmc ...; "	\