Thermal: Intel SoC: fix simple_return.cocci warnings

drivers/thermal/intel_soc_dts_iosf.c:358:4-7: WARNING: end returns can be simpified

 Simplify a trivial if-return sequence.  Possibly combine with a
 preceding function call.
Generated by: scripts/coccinelle/misc/simple_return.cocci

CC: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>