The ret variable in mtk_hdmi_pll_calc() was used unitialized as reported
by the kernel test robot.
Fix the issue by removing the variable altogether and testing out the
return value of mtk_hdmi_pll_set_hw()
Fixes: 45810d486bb44 ("phy: mediatek: add support for phy-mtk-hdmi-mt8195")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>