While the build system supports this for a long time, this was
never documented. Add a documentation for it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 380284026c13..a52b311cdadc 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -124,4 +124,6 @@ dochelp:
 	@echo
 	@echo  '  make DOCS_CSS={a .css file} adds a DOCS_CSS override file for html/epub output.'
 	@echo
+	@echo  '  make PAPER={a4|letter} Specifies the paper size used for LaTeX/PDF output.'
+	@echo
 	@echo  '  Default location for the generated documents is Documentation/output'
-- 
2.51.0