pinctrl: sunxi: Fix SPDIF function name for A83T

We use well known standard names for functions that have name, such as
I2C, SPI, SPDIF, etc..

Fix the function name of SPDIF, which was named OWA (One Wire Audio)
based on Allwinner datasheets.

Fixes: 4730f33f ("pinctrl: sunxi: add allwinner A83T PIO controller
		      support")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>