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/northbridge/amd/amdmct/mct_ddr3/mct_d.c

@@ -36,7 +36,7 @@
 #include <northbridge/amd/amdfam10/debug.h>
 #include <northbridge/amd/amdfam10/raminit.h>
 #include <northbridge/amd/amdfam10/amdfam10.h>
-#include <reset.h>
+#include <southbridge/amd/common/reset.h>
 #include <cpu/x86/msr.h>
 #include <cpu/amd/msr.h>
 #include <arch/acpi.h>