drm: bridge/dw_hdmi: clean up hdmi_set_clk_regenerator()

Clean up hdmi_set_clk_regenerator() by allowing it to take the audio
sample rate and ratio directly, rather than hiding it inside the
function.  Raise the unsupported pixel clock/sample rate message from
debug to error level as this results in audio not working correctly.

Tested-by: Yakir Yang <ykk@rock-chips.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>