board: ge: bx50v3, mx53ppd: fix firstboot detection

Use `test' command to test for file existence instead of relying on the
old functionality of the `ext2load' command (which now reports an error
when attempting to load a zero length file).

Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Signed-off-by: Ian Ray <ian.ray@ge.com>
diff --git a/include/configs/mx53ppd.h b/include/configs/mx53ppd.h
index a4452b8..101abc4 100644
--- a/include/configs/mx53ppd.h
+++ b/include/configs/mx53ppd.h
@@ -72,8 +72,8 @@
 		"rootwait ${bootargs}\0" \
 	"doquiet=if ext2load ${dev} ${devnum}:5 0x7000A000 /boot/console; " \
 		"then setenv quiet; fi\0" \
-	"hasfirstboot=ext2load ${dev} ${devnum}:${partnum} 0x7000A000 " \
-		"/boot/bootcause/firstboot\0" \
+	"hasfirstboot=" \
+		"test -e ${dev} ${devnum}:${partnum} /boot/bootcause/firstboot\0" \
 	"swappartitions=setexpr partnum 3 - ${partnum}\0" \
 	"failbootcmd=" \
 		"cls; " \