thermal:samsung: fix compilation warning

This patch fixes a compilation warning.

warning: passing argument 5 of 'thermal_zone_device_register' discards 'const'
qualifier from pointer target type [enabled by default]
include/linux/thermal.h:270:29: note: expected 'struct thermal_zone_device_ops *'
but argument is of type 'const struct thermal_zone_device_ops *'

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>