hal: spkr_prot: read temperature once during calibration

Currently temperature read happens multiple times during thermal
calibration to get the equilibrium temperature. This is not
required as speaker amplifier temperature does not change over
iterations. Read the temperature only once to avoid delay in
speaker thermal calibration.

Change-Id: Ie121ea3e37697ee14e24d8ccd68c697c0220f0ab
1 file changed