target-i386: use memory API to implement SMRAM

Remove cpu_smm_register and cpu_smm_update.  Instead, each CPU
address space gets an extra region which is an alias of
/machine/smram.  This extra region is enabled or disabled
as the CPU enters/exits SMM.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

bsd-user/main.c

@@ -108,10 +108,6 @@ void cpu_list_unlock(void)
 /***********************************************************/
 /* CPUX86 core interface */
 
-void cpu_smm_update(CPUX86State *env)
-{
-}
-
 uint64_t cpu_get_tsc(CPUX86State *env)
 {
     return cpu_get_real_ticks();