docs/manual: simplify generation dependencies

The document's main file is already part of MANUAL_SOURCES, so no need
to explicitly depend on it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Acked-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/manual/manual.mk

@@ -98,8 +98,7 @@ $$(O)/docs/$(1)/$(1).$(4):
 		to make through the command line: \
 		'PATH=/path/to/custom-xsltproc/bin:$$$${PATH} make manual-pdf')
 else
-$$(O)/docs/$(1)/$(1).$(4): docs/$(1)/$(1).txt \
-			   $$($$(call UPPERCASE,$(1))_SOURCES) \
+$$(O)/docs/$(1)/$(1).$(4): $$($$(call UPPERCASE,$(1))_SOURCES) \
 			   manual-check-dependencies \
 			   manual-check-dependencies-$(3) \
 			   manual-prepare-sources