max8925_power: Fix incorrect voltage and current calculation
The datasheet indicates a 12 bit value is returned for i2c
registers for voltage and current. Code was assuming 8 bits.
But default for chip is 12 bit return value.
Voltage is returned in 2mV units -- adjust to return as uV
per linux power spec
Adjust current calculation to return units in uA.
Signed-off-by: Philip Rakity <prakity@marvell.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>