mfd: da9063: Rename PMIC_DA9063 to PMIC_CHIP_ID_DA9063

The PMIC_DA9063 is a complete misnomer, it denotes the value of the
DA9063 chip ID register, so rename it as such. It is also the value
of chip ID register of DA9063L though, so drop the enum as all the
DA9063 "models" share the same chip ID and thus the distinction will
have to be made using DT or otherwise.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>