xtensa: intel_s1000: Remove redundant call to soc_get_ref_clk_freq

Call to soc_get_ref_clk_freq function is redundant in soc.c as it
simply returns a global static variable. Hence removed that call.

Signed-off-by: Rajavardhan Gundi <rajavardhan.gundi@intel.com>

soc/xtensa/intel_s1000/soc.c

@@ -238,7 +238,6 @@ static int soc_init(struct device *dev)
 {
 	soc_read_bootstraps();
 
-	ref_clk_freq = soc_get_ref_clk_freq();
 	LOG_INF("Reference clock frequency: %u Hz", ref_clk_freq);
 
 	soc_set_resource_ownership();