Replace hlt with halt()

There were instances of unneeded arch/hlt.h includes,
various hlt() calls that weren't supposed to exit (but
might have) and various forms of endless loops around
hlt() calls.

All these are sorted out now: unnecessary includes are
dropped, hlt() is uniformly replaced with halt() (except
in assembly, obviously).

Change-Id: I3d38fed6e8d67a28fdeb17be803d8c4b62d383c5
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: http://review.coreboot.org/7608
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/cpu/intel/model_206ax/bootblock.c

@@ -23,6 +23,7 @@
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>
 #include <arch/io.h>
+#include <halt.h>
 
 #include <cpu/intel/microcode/microcode.c>
 #include "model_206ax.h"
@@ -110,7 +111,7 @@ static void set_flex_ratio_to_tdp_nominal(void)
 	/* Issue warm reset, will be "CPU only" due to soft reset data */
 	outb(0x0, 0xcf9);
 	outb(0x6, 0xcf9);
-	asm("hlt");
+	halt();
 }
 
 static void bootblock_cpu_init(void)