Issue warning when deprecated -no-kvm-pit is used

Releases of qemu-kvm will be interrupted at qemu 1.3.0.
Users should switch to plain qemu releases.
To avoid breaking scenarios which are setup with command line
options specific to qemu-kvm, port these switches from qemu-kvm
to qemu.git.

Port -no-kvm-pit option.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/vl.c b/vl.c
index 7d0708a..37717b4 100644
--- a/vl.c
+++ b/vl.c
@@ -3171,6 +3171,11 @@
                     machine = machine_parse(optarg);
                 }
                 break;
+            case QEMU_OPTION_no_kvm_pit: {
+                fprintf(stderr, "Warning: KVM PIT can no longer be disabled "
+                                "separately.\n");
+                break;
+            }
             case QEMU_OPTION_usb:
                 machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
                 if (machine_opts) {