reset: Finalize move to new API

Move soft_reset() to `southbridge/amd/common/` it's only used for
amdfam10 now.

Drop hard_reset() for good.

Change-Id: Ifdc5791160653c5578007f6c1b96015efe2b3e1e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/29059
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/Kconfig

@@ -449,13 +449,6 @@ config RESUME_PATH_SAME_AS_BOOT
 	  same path as a regular boot. e.g. an x86 system runs from the
 	  reset vector at 0xfffffff0 on both resume and warm/cold boot.
 
-config HAVE_HARD_RESET
-	bool
-	default n
-	help
-	  This variable specifies whether a given board has a hard_reset
-	  function, no matter if it's provided by board code or chipset code.
-
 config HAVE_ROMSTAGE_CONSOLE_SPINLOCK
 	bool
 	depends on EARLY_CBMEM_INIT