kvm: assume that many ioeventfds can be created

NR_IOBUS_DEVS was increased to 200 in Linux 2.6.34.  By Linux 3.5 it had
increased to 1000 and later ioeventfds were changed to not count against
the limit.  But the earlier limit of 200 would already be enough for
kvm_check_many_ioeventfds() to be true, so remove the check.

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

accel/stubs/kvm-stub.c

@@ -40,11 +40,6 @@ bool kvm_has_sync_mmu(void)
     return false;
 }
 
-int kvm_has_many_ioeventfds(void)
-{
-    return 0;
-}
-
 int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
 {
     return 1;