drm/msm/hdmi: drop the hdmi-mux support

With the last (and only) in-kernel user of hdmi-mux regulator, drop it
from the HDMI driver.
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/488855/
Link: https://lore.kernel.org/r/20220609122350.3157529-6-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/hdmi/hdmi.c

@@ -361,7 +361,7 @@ static const char *hpd_reg_names_none[] = {};
 
 static struct hdmi_platform_config hdmi_tx_8660_config;
 
-static const char *hpd_reg_names_8960[] = {"core-vdda", "hdmi-mux"};
+static const char *hpd_reg_names_8960[] = {"core-vdda"};
 static const char *hpd_clk_names_8960[] = {"core", "master_iface", "slave_iface"};
 
 static struct hdmi_platform_config hdmi_tx_8960_config = {