docs-rst: fix a breakage when building PDF documents

changeset 606b9ac81a63 ("doc-rst: generic way to build only sphinx
sub-folders") accidentally broke PDF generation by adding an extra
")". Remove it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/Makefile.sphinx

@@ -71,7 +71,7 @@ ifeq ($(HAVE_PDFLATEX),0)
 	$(warning The 'pdflatex' command was not found. Make sure you have it installed and in PATH to produce PDF output.)
 	@echo "  SKIP    Sphinx $@ target."
 else # HAVE_PDFLATEX
-	@$(call loop_cmd,sphinx,latex,.,latex,.))
+	@$(call loop_cmd,sphinx,latex,.,latex,.)
 	$(Q)$(MAKE) -C $(BUILDDIR)/latex
 endif # HAVE_PDFLATEX