fix: ext4: indicate via a block bitmap read is prefetched… (v5.9)

fix: ext4: indicate via a block bitmap read is prefetched… (v5.9)

See upstream commit:

  commit ab74c7b23f3770935016e3eb3ecdf1e42b73efaa
  Author: Theodore Ts'o <tytso@mit.edu>
  Date:   Wed Jul 15 11:48:55 2020 -0400

    ext4: indicate via a block bitmap read is prefetched via a tracepoint

    Modify the ext4_read_block_bitmap_load tracepoint so that it tells us
    whether a block bitmap is being prefetched.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0e5e2c5b8004223d0928235c092449ee16a940e1