include/get.sh: 3-way merge on git am

this will make managing updates easier. which will
be soon, because i have a lot of patches.

no idea why i didn't add this before. normally, i just
copy a directory and git-fetch, then cherry-pick as
i please. this will make it trivial to just update
a revision and merge the patches. then i can just
intervene only when necessary, on a given src tree.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/get.sh

@@ -443,7 +443,7 @@ tmpclone()
 
 	while read -r tmpclone_patch; do
 
-		( x_ git -C "$2" am --keep-cr "$tmpclone_patch" ) || \
+		( x_ git -C "$2" am -3 --keep-cr "$tmpclone_patch" ) || \
 		    err "Can't apply '$tmpclone_patch'" "tmpclone" "$@"; :
 
 	done < "$tmpclone_patchlist" || \