intel: Use CF9 reset (part 2)

Make use of the common CF9 reset in SOC_INTEL_COMMON_RESET. Also
implement board_reset() as a "full reset" (aka. cold reset) as that
is what was used here for hard_reset().

Drop soc_reset_prepare() thereby, as it was only used for APL. Also,
move the global-reset logic.

We leave some comments to remind us that a system_reset() should
be enough, where a full_reset() is called now (to retain current
behaviour) and looks suspicious.

Note, as no global_reset() is implemented for Denverton-NS, we halt
there now instead of issuing a non-global reset. This seems safer;
a non-global reset might result in a reset loop.

Change-Id: I5e7025c3c9ea6ded18e72037412b60a1df31bd53
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/29169
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/quark/Kconfig

@@ -28,7 +28,6 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_VERSTAGE_X86_32
 	select BOOTBLOCK_SAVE_BIST_AND_TIMESTAMP
 	select C_ENVIRONMENT_BOOTBLOCK
-	select HAVE_HARD_RESET
 	select HAVE_MONOTONIC_TIMER
 	select NO_MMCONF_SUPPORT
 	select REG_SCRIPT