arch/x86: Avoid HAVE_SMI_HANDLER conditional with smm-class

Build of the entire smm-class is skipped if we have
HAVE_SMI_HANDLER=n.

Change-Id: I10b4300ddd18b1673c404b45fd9642488ab3186c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34125
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Lance Zhao <lance.zhao@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/amd/agesa/family15tn/Makefile.inc

@@ -19,7 +19,7 @@ ramstage-y += fixme.c
 ramstage-y += chip_name.c
 ramstage-y += model_15_init.c
 
-smm-$(CONFIG_HAVE_SMI_HANDLER) += udelay.c
+smm-y += udelay.c
 
 subdirs-y += ../../mtrr
 subdirs-y += ../../smm

src/cpu/amd/pi/00630F01/Makefile.inc

@@ -19,7 +19,7 @@ ramstage-y += fixme.c
 ramstage-y += chip_name.c
 ramstage-y += model_15_init.c
 
-smm-$(CONFIG_HAVE_SMI_HANDLER) += udelay.c
+smm-y += udelay.c
 
 subdirs-y += ../../mtrr
 subdirs-y += ../../smm