x86: sysreset: Move priv/plat structs to headers

With the new of-platdata, these need to be available to dt_platdata.c
so must be in header files. Move them and add the dtd struct too.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/drivers/sysreset/sysreset_x86.c b/drivers/sysreset/sysreset_x86.c
index 8f99703..8042f39 100644
--- a/drivers/sysreset/sysreset_x86.c
+++ b/drivers/sysreset/sysreset_x86.c
@@ -13,10 +13,7 @@
 #include <acpi/acpi_s3.h>
 #include <asm/io.h>
 #include <asm/processor.h>
-
-struct x86_sysreset_plat {
-	struct udevice *pch;
-};
+#include <asm/sysreset.h>
 
 /*
  * Power down the machine by using the power management sleep control