drm: bridge: dw_hdmi: add reset function for PHY GEN1

PHY reset register(MC_PHYRSTZ) active high reset control for PHY GEN2,
and active low reset control for PHY GEN1.

Rename function dw_hdmi_phy_reset to dw_hdmi_phy_gen2_reset.
Add dw_hdmi_phy_gen1_reset function for PHY GEN1.

Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/e0b3be2d63fe3e95246fb8b8b0dcd57415b29e04.1649989179.git.Sandor.yu@nxp.com