write_ext2_file.sh: Fix partition number warning

/boot is '1' on the phone

scripts/write_ext2_file.sh

@@ -6,7 +6,7 @@ if [ $# -lt 2 ]; then
     echo "Usage: $0 <file> <mmc_dev[:part]>"
     echo "*************************************************************"
     echo "* Until u-boot is updated to mainline don't try to write to *"
-    echo "* anything other than partition 0. Writing to partition 1   *"
+    echo "* anything other than partition 1. Writing to partition 2   *"
     echo "* will DESTROY your rootfs !                                *"
     echo "*************************************************************"
     exit 1