SPDIF can derive a TX clock for playback from one of its clock sources --
spdif root clock to match its supporting sample rates. So this patch set
the spdif root clock's parent to pll3_pfd3_454m since the pll3_pfd3_454m
can approximately meet its sample rate requirement.
Signed-off-by: NNicolin Chen <Guangyu.Chen@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>