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

Remove the register DA9062AA_BBAT_CONT (0x0C5) from the DA9061 chip model
regmap access ranges. This applies to both da9061_aa_readable_ranges[]
and da9061_aa_writeable_ranges[].

This change is to correct the DA9061 chip model and align it with the
latest DA9061 Datasheet.

This register previously appeared in the DA9061 Datasheet, Revision 3.2,
01-Mar-2016 and has been removed from later DA9061 datasheet from Dialog,
Revision 3.3, 04-Apr-2017.

Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>