This reverts commit ec7bd784.

This field rename was done to reuse defer_syc list head for multiple
lists. That's not needed anymore and this list head will only be used
for defer sync. So revert this patch to avoid conflicts with the other
reverts coming after this.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-3-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>