x86: Switch to use DM sysreset driver

This converts all x86 boards over to DM sysreset.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

arch/x86/include/asm/processor.h

@@ -43,11 +43,6 @@ enum {
 	FULL_RST	= 1 << 3,	/* full power cycle */
 };
 
-/**
- * x86_full_reset() - reset everything: perform a full power cycle
- */
-void x86_full_reset(void);
-
 static inline __attribute__((always_inline)) void cpu_hlt(void)
 {
 	asm("hlt");