KVM: PPC: Book3S: Remove duplicate setting of the B field in tlbie

Remove duplicate setting of the the "B" field when doing a tlbie(l).
In compute_tlbie_rb(), the "B" field is set again just before
returning the rb value to be used for tlbie(l).

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>