drm/msm/dsi: Drop redundant NULL-ifying of clocks on error paths

drm/msm/dsi: Drop redundant NULL-ifying of clocks on error paths

dsi_clk_init(), which gets the clocks, is called only through platform
driver probe and its failure is a failure of the probe.  Therefore
NULL-ifying specific clocks is pointless and redundant - the PTR_ERR
value stored there won't be used/dereferenced afterwards.  What's more,
variant-specific clock init calls like dsi_clk_init_6g_v2() are not
doing this cleanup.  Dropping redundant code allows later to make this a
bit simpler.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/637303/
Link: https://lore.kernel.org/r/20250214-drm-msm-cleanups-v2-1-1bec50f37dc1@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>