[U-Boot] [PATCH] Makefile: Fix make clean with DocBook

[Jagan Teki]

doc/DocBook has removed in below commit
"doc: Replace DocBook with sphinx-based docs"
(sha1: 78a88f7930becb78afef09c1237a8e4edc1b01e1)

and missed to remove it from clean-dirs, otherwise
'make clean' shows an error as below.

$ make clean
scripts/Makefile.clean:15: doc/DocBook/Makefile: No such file or directory
make[1]: *** No rule to make target 'doc/DocBook/Makefile'.  Stop.
Makefile:1610: recipe for target '_clean_doc/DocBook' failed
make: *** [_clean_doc/DocBook] Error 2

Cc: Mario Six <mario.six at gdsys.cc>
Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
---
 Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index d1246e063f..5224c34c96 100644
--- a/Makefile
+++ b/Makefile
@@ -1603,7 +1603,7 @@ clean: rm-files := $(CLEAN_FILES)
 
 clean-dirs	:= $(foreach f,$(u-boot-alldirs),$(if $(wildcard $(srctree)/$f/Makefile),$f))
 
-clean-dirs      := $(addprefix _clean_, $(clean-dirs) doc/DocBook)
+clean-dirs      := $(addprefix _clean_, $(clean-dirs))
 
 PHONY += $(clean-dirs) clean archclean
 $(clean-dirs):
@@ -1685,7 +1685,6 @@ help:
 	@echo  '  coccicheck      - Execute static code analysis with Coccinelle'
 	@echo  ''
 	@echo  'Documentation targets:'
-	@$(MAKE) -f $(srctree)/doc/DocBook/Makefile dochelp
 	@echo  ''
 	@echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
 	@echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
-- 
2.17.1