cpu: update info related direction into BP if mispredicted.

cpu: update info related direction into BP if mispredicted.

Update direction info of a branch into BP if, the branch is not
found in the target buffer. Therefore, this  updated direction is
used to squash the branch later on. Previously, some mispredicted
branches were not sqaushed as the BP had old info.

Reported-by: Dimitrios Chasapis
Change-Id: I4be2eb706edc5ffa9935948fb52a01667286c721
jira-issue: https://gem5.atlassian.net/browse/GEM5-355
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25903
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Ayaz Akram <yazakram@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Dimitrios Chasapis <k4s4s.heavener@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>