misc: qemu_vfat: update for new mount table values

Refer rtems.git commit 29e92b090c8bc35745aa5c89231ce806bcb11e57 for
more info
Bug: https://www.rtems.org/bugzilla/show_bug.cgi?id=2155
misc: Support building qemu_vfat with waf
Merge pull request #22 from chirayudesai/qemu_vfat-fix

Qemu vfat fix