ASoC: fsl: align mpc8610_hpcd with p1022_ds on getting codec node

Align mpc8610_hpcd with p1022_ds on getting codec node by just calling
of_parse_phandle.  The bonus point of doing that is we can save
exporting get_node_by_phandle_name() when we consolidate the common
bits between mpc8610_hpcd and p1022_ds into a module, which can be
shared by more machine drivers added later.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>