ASoC: Writing register default value for the reset register

The WM8983 can be reset by performing a write of any value to
the software reset register.
To avoid writing to the software reset register while resume,
we should write the same value in wm8983_reg_defs to software
reset register in wm8983_probe().
The write to the reset register is suppressed by the cache
restore code when it skips writes of default registers.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>