disp: msm: sde: correct line time to include compression ratio

Current computation of line time does not include compression ratio
from either DSC or VDC. This change stores source bpp and target bpp in
sde_crtc during sde encoder mode set to be used while calculating line
time.

Change-Id: Ib1e045dce17fcf006447d4562b402cc3f214ed8c
Signed-off-by: Samantha Tran <samtran@codeaurora.org>