msm: vidc: fix line buffer bw voting for ar50

In ar50 decoder case, line buffer bw was calculated
but not added in the total ddr bw, which will cause
huge undervoting.

Add line buffer read/write bw to total ddr bw.

Change-Id: Ib702907c148828cd51ff351a3e48b57b0405b0f4
Signed-off-by: Dikshita Agarwal <dikshita@codeaurora.org>