power: pmic_pca9450: fix PCA9450A I2C address

Quoting Ye Li from NXP:

    "We have confirmed with PMIC team, 0x35 is used only on early chips
    and not used any more. 0x25 is the final address."

Fix it by merging power_pca9450a_init and power_pca9450b_init into one
function power_pca9450_init.

Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Ye Li <ye.li@nxp.com>