qemu-io: Split off commands to qemu-io-cmds.c

This is the implementation of all qemu-io commands that make sense to be
called from the qemu monitor, i.e. everything except open, close and
quit.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Makefile

@@ -186,7 +186,7 @@ qemu-img.o: qemu-img-cmds.h
 
 qemu-img$(EXESUF): qemu-img.o $(block-obj-y) libqemuutil.a libqemustub.a
 qemu-nbd$(EXESUF): qemu-nbd.o $(block-obj-y) libqemuutil.a libqemustub.a
-qemu-io$(EXESUF): qemu-io.o cmd.o $(block-obj-y) libqemuutil.a libqemustub.a
+qemu-io$(EXESUF): qemu-io.o qemu-io-cmds.o cmd.o $(block-obj-y) libqemuutil.a libqemustub.a
 
 qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o