Add TAGS and *~ to .gitignore

Add the etags output generated by "make TAGS" and editor backup files
to .gitignore.

This patch has previously appeared in my series of patches to add
pSeries emulation support.  However, it obviously has no real
connection to that, and can be applied seperately.

Please apply.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

.gitignore

@@ -63,3 +63,5 @@ pc-bios/optionrom/multiboot.raw
 .stgit-*
 cscope.*
 tags
+TAGS
+*~