Make kernel, initrd and append be machine_opts

Make kernel, initrd, append be machine opts (ie -machine kernel=foo)
with the old plain command line arguments as legacy/convenience
equivalents.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qemu-config.c b/qemu-config.c
index c9763e0..7d9da78 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -566,6 +566,18 @@
             .name = "kvm_shadow_mem",
             .type = QEMU_OPT_SIZE,
             .help = "KVM shadow MMU size",
+        }, {
+            .name = "kernel",
+            .type = QEMU_OPT_STRING,
+            .help = "Linux kernel image file",
+        }, {
+            .name = "initrd",
+            .type = QEMU_OPT_STRING,
+            .help = "Linux initial ramdisk file",
+        }, {
+            .name = "append",
+            .type = QEMU_OPT_STRING,
+            .help = "Linux kernel command line",
         },
         { /* End of list */ }
     },