mfd: arizona: Remove redundant register sync

This soft reset used to be located after the register patch had been
applied, but has since moved to before the patch is applied. At the new
location there is no requirement to do a register sync as no register
writes will have happened yet.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>