pinctrl: uniphier: divide I2S and S/PDIF audio out pin-mux group

pinctrl: uniphier: divide I2S and S/PDIF audio out pin-mux group

This patch divides large pin-mux group 'aio' of UniPhier LD11/LD20
to 2 groups as following:
  aout1   : 8ch I2S output: AO1DACCK, AO1BCK, AO1LRCK, AO1D[0-2]
  aoutiec1: S/PDIF output : AO1IEC, AO1ARC

Signed-off-by: Katsuhiro Suzuki <suzuki.katsuhiro@socionext.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>