drm/msm/dsi: Print dual-DSI-adjusted pclk instead of original mode pclk

When dual-DSI (bonded DSI) was added in commit ed9976a0
("drm/msm/dsi: adjust dsi timing for dual dsi mode") some DBG() prints
were not updated, leading to print the original mode->clock rather
than the adjusted (typically the mode clock divided by two, though more
recently also adjusted for DSC compression) msm_host->pixel_clk_rate
which is passed to clk_set_rate() just below.  Fix that by printing the
actual pixel_clk_rate that is being set.

Fixes: ed9976a0

 ("drm/msm/dsi: adjust dsi timing for dual dsi mode")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/589896/
Link: https://lore.kernel.org/r/20240417-drm-msm-initial-dualpipe-dsc-fixes-v1-1-78ae3ee9a697@somainline.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>