util/gitconfig: Replace printf with heredoc

The `gitconfig.sh` script contains a call to `printf` with a lengthy
argument where no format string is used at all. Replace it with a
heredoc for better readability.

Change-Id: I42dbaa570ab9661991fa5d9b4577c9aed05c2981
Signed-off-by: Alex Thiessen <alex.thiessen.de+coreboot@gmail.com>
Reviewed-on: https://review.coreboot.org/23251
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/gitconfig/gitconfig.sh

@@ -65,7 +65,10 @@ git submodule update --init --checkout"
 
 { git config --includes user.name && \
 	git config --includes user.email; } >/dev/null || \
-	{ printf "Please configure your name and email in git:\n\n\
- git config --global user.name \"Your Name Comes Here\"\n\
- git config --global user.email your.email@example.com\n"; \
+	{ cat <<-EOMSG
+		Please configure your name and email in git:
+
+		 git config --global user.name "Your Name Comes Here"
+		 git config --global user.email your.email@example.com
+EOMSG
 exit 1; }