drm/msm/dsi: fix msm_dsi_phy_get_clk_provider return code

msm_dsi_phy_get_clk_provider() always returns two provided clocks, so
return 0 instead of returning incorrect -EINVAL error code.

Fixes: 5d134596

 ("drm/msm/dsi: push provided clocks handling into a generic code")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Tested-by: Jonathan Marek <jonathan@marek.ca>
Link: https://lore.kernel.org/r/20210412000158.2049066-1-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>