hwmon: qpnp-adc: Fix voltage scaling for VADC_HC peripheral

Incorrect voltage and temperature results are seen
during ADC reads from VADC_HC peripheral.

Fix setting the correct flag used to select the respective
peripherals scaling formula to return the correct voltage
and temperature readings for VADC_HC peripheral.

Change-Id: I6f4fe857996c8df996b6e4a0e4475a48740929fa
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>