This is git. It's normal to have multiple patch files. If you look on mailing
lists, you'll see that. Look on the mailing list of the kernel named Linus
and you'll see email threads [PATCH 1/5] which is patch 1 of 5. You can use
git send-email to send them (which needs some set up first.)
If you really do one one file there are multiple options, of course since
this is git: There's more than one way to do things. :)
You could squash the commits, make a temporary branch and merge things, or
try this when doing format-patch:
--stdout > this_is_my_amazing_single_patch_file.diff
