spmi: pmic-arb: rename spmi_pmic_arb_dev to spmi_pmic_arb
Usually *_dev best used for structures that embed a struct device in
them. spmi_pmic_arb_dev doesn't embed one. It is simply a driver data
structure. Use an appropriate name for it.
Also there are many places in the driver that left shift the bit to
generate a bit mask. Replace it with the BIT() macro.