thermal: exynos_thermal: Suppress the debug print for temperature change.

Suppress the debug prints, it overrides the kernel debug messages.

[ 127.273507] [c0] tmu temperature state 0 to 2, cur_temp : 96
[ 127.282718] [c0] tmu temperature state 2 to 0, cur_temp : 95
[ 127.351033] [c0] tmu temperature state 0 to 2, cur_temp : 96
[ 127.367993] [c0] tmu temperature state 2 to 0, cur_temp : 94

Change-Id: I58b3b7db7c48f59eac5ad4ed33cd1fbd44f49aa2
(cherry picked from commit 52b568462779944910c7684f7384ffa320a65be3)