Revert "mfd: da9061: Fix to remove BBAT_CONT register from chip model"

This patch was applied to the MFD twice, causing unwanted behavour.

This reverts commit b77eb79a.

Fixes: b77eb79a

 ("mfd: da9061: Fix to remove BBAT_CONT register from chip model")
Reported-by: Steve Twiss <stwiss.opensource@diasemi.com>
Reviewed-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>