target/i386: Remove unused KVM stubs

All these functions:

 - kvm_arch_get_supported_cpuid()
 - kvm_has_smm(()
 - kvm_hyperv_expand_features()
 - kvm_set_max_apic_id()

are called after checking for kvm_enabled(), which is
false when KVM is not built. Since the compiler elides
these functions, their stubs are not used and can be
removed.

Inspired-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-7-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/kvm/kvm-stub.c

@@ -10,42 +10,16 @@
  *
  */
 #include "qemu/osdep.h"
-#include "cpu.h"
 #include "kvm_i386.h"
 
 #ifndef __OPTIMIZE__
-bool kvm_has_smm(void)
-{
-    return 1;
-}
-
 bool kvm_enable_x2apic(void)
 {
     return false;
 }
-
-/* This function is only called inside conditionals which we
- * rely on the compiler to optimize out when CONFIG_KVM is not
- * defined.
- */
-uint32_t kvm_arch_get_supported_cpuid(KVMState *env, uint32_t function,
-                                      uint32_t index, int reg)
-{
-    abort();
-}
 #endif
 
 bool kvm_hv_vpindex_settable(void)
 {
     return false;
 }
-
-bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp)
-{
-    abort();
-}
-
-void kvm_set_max_apic_id(uint32_t max_apic_id)
-{
-    return;
-}