drm/msm/mdp4: correct LCDC regulator name

Correct c&p error from the conversion of LCDC regulators to the bulk
API.

Fixes: 54f1fbcb ("drm/msm/mdp4: use bulk regulators API for LCDC encoder")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/590412/
Link: https://lore.kernel.org/r/20240420-mdp4-fixes-v1-3-96a70f64fa85@linaro.org