lib: Add Kconfig to toggle boot state debugging

Add the DEBUG_BOOT_STATE Kconfig value to enable boot state debugging.
Update include/bootstate.h and lib/hardwaremain.c to honor this value.
Add a dashed line which displays between the states.

Testing on Galileo:
* select DEBUG_BOOT_STATE in mainboard/intel/galileo/Kconfig
* Build and run on Galileo

Change-Id: I6e8a0085aa33c8a1394f31c030e67ab3d5bf7299
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/13716
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/Kconfig

@@ -1149,3 +1149,10 @@ config CBFS_SIZE
 	  This is the part of the ROM actually managed by CBFS.  Set it to be
 	  equal to the full rom size if that hasn't been overridden by the
 	  chipset or mainboard.
+
+config DEBUG_BOOT_STATE
+	bool
+	default n
+	help
+	  Control debugging of the boot state machine.  When selected displays
+	  the state boundaries in ramstage.