disp: msm: sde: add changes to wait for only one WB_DONE irq

With WB encoder added in the drm encoder_list before primary
encoder introduced as part of commit d28ebf05 ("disp:
msm: sde: populate WB display encoder list before dsi"),
sde_kms_wait_for_commit_done during CWB usecase is causing
crtc_commit thread to wait for two WB frame done irqs causing
janks on primary. Add changes to unblock crtc_commit thread and wait
for only one WB frame done irq.

Change-Id: Ie298302fea9df8ba5a1c2fa04f5f585ae455e0c9
Signed-off-by: Jayaprakash <jmadiset@codeaurora.org>