thermal: intel: int3403: replace printk(KERN_WARN...) with pr_warn(...)

Direct invocation of printk() is not preferred to emit logs.
This commit replaces printk(KERN_WARNING) with corresponding
pr_warn() function call.

Signed-off-by: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>