thermal: tsens: fix compilation warning

Initialize calibration data for calibration less mode.
This eliminates compilation warning too.

drivers/thermal/msm8974-tsens.c:896:34: warning: 'calib_data[1]'
may be used uninitialized in this function [-Wuninitialized]

Change-Id: I715f28a7c0787435dcbbff8f48f26eae64b5f820
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>