drm/rockchip: dw_hdmi: Do not leave clock enabled in error case

The driver returns an error when devm_phy_optional_get() fails leaving
the previously enabled clock turned on. Change order and enable the
clock only after the phy has been acquired.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220126145549.617165-3-s.hauer@pengutronix.de