cpu/x86: Declare SMM_ASEG

This is really an inverse of SMM_TSEG to flag
platforms that should potentially move away
from ASEG implementation.

Change-Id: I3b9007c55c75a59a9e6acc0a0e701300f7d21f87
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34134
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/Kconfig

@@ -543,10 +543,6 @@ config HAVE_OPTION_TABLE
 	  file containing NVRAM/CMOS bit definitions.
 	  It defaults to 'n' but can be selected in mainboard/*/Kconfig.
 
-config HAVE_SMI_HANDLER
-	bool
-	default n
-
 config PCI_IO_CFG_EXT
 	bool
 	default n