Replace hlt() loops with halt()

Change-Id: I8486e70615f4c404a342cb86963b5357a934c41d
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: http://review.coreboot.org/7606
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/cpu/intel/haswell/romstage.c

@@ -25,6 +25,7 @@
 #include <cpu/x86/bist.h>
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>
+#include <halt.h>
 #include <lib.h>
 #include <timestamp.h>
 #include <arch/io.h>
@@ -49,9 +50,7 @@
 static inline void reset_system(void)
 {
 	hard_reset();
-	while (1) {
-		hlt();
-	}
+	halt();
 }
 
 /* The cache-as-ram assembly file calls romstage_main() after setting up