Add qapi related generated files to .gitignore

.gitignore already lists the qapi-generated subdirectory which includes a
number of files generated during build.  However, there are some additional
files generated by the qapi build which go in the top level directory.

This patch adds them to .gitignore, removing the irritating noise from
diffs and the like.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

.gitignore

@@ -17,6 +17,10 @@ libhw64
 libuser
 linux-headers/asm
 qapi-generated
+qapi-types.[ch]
+qapi-visit.[ch]
+qmp-commands.h
+qmp-marshal.c
 qemu-doc.html
 qemu-tech.html
 qemu-doc.info