sh: fix rsk7203 and MigoR out of tree build

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

Makefile

@@ -3210,7 +3210,7 @@ mimc200_config		:	unconfig
 rsk7203_config: unconfig
 	@ >include/config.h
 	@echo "#define CONFIG_RSK7203 1" >> include/config.h
-	@./mkconfig -a $(@:_config=) sh sh2 rsk7203 renesas
+	@$(MKCONFIG) -a $(@:_config=) sh sh2 rsk7203 renesas
 
 #########################################################################
 ## sh3 (Renesas SuperH)
@@ -3233,7 +3233,7 @@ ms7720se_config: unconfig
 MigoR_config :       unconfig
 	@mkdir -p $(obj)include
 	@echo "#define CONFIG_MIGO_R 1" > $(obj)include/config.h
-	@./mkconfig -a $(@:_config=) sh sh4 MigoR renesas
+	@$(MKCONFIG) -a $(@:_config=) sh sh4 MigoR renesas
 
 ms7750se_config: unconfig
 	@mkdir -p $(obj)include