drm/msm/dsi_phy_14nm: convert from divider_round_rate() to divider_determine_rate()

drm/msm/dsi_phy_14nm: convert from divider_round_rate() to divider_determine_rate()

The divider_round_rate() function is now deprecated, so let's migrate
to divider_determine_rate() instead so that this deprecated API can be
removed.

Note that when the main function itself was migrated to use
determine_rate, this was mistakenly converted to:

    req->rate = divider_round_rate(...)

This is invalid in the case when an error occurs since it can set the
rate to a negative value.

Fixes: cc41f29a6b04 ("drm/msm/dsi_phy_14nm: convert from round_rate() to determine_rate()")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/697613/
Link: https://lore.kernel.org/r/20260108-clk-divider-round-rate-v1-24-535a3ed73bf3@redhat.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>