spmi: pmic-arb: return __iomem pointer instead of offset

Modify the pmic_arb version ops to return an __iomem pointer
to the address instead of an offset. That way we do not need to
care about the base address changes in the new HW version.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>