hwmon: qpnp-adc-voltage: Update default scale function for VADC

ADC channel values that uses absolute calibration and default
scale function are out of range.

Scale voltage should be multiplied by thousand for non absolute
channels that uses default scale function. Update the condition
accordingly.

Change-Id: Ibfa35109e4bf930bb495fff8fa6494d51b12a76b
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>