kbuild: tools: fix a bug that always builds Denx logo

LOGO_BMP was never overwritten by board-specific or
vendor-specific logos.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Bo Shen <voice.shen@atmel.com>
Tested-by: Bo Shen <voice.shen@atmel.com>

tools/Makefile

@@ -157,10 +157,10 @@ ifeq ($(LOGO_BMP),)
 LOGO_BMP= $(srctree)/$(src)/logos/denx.bmp
 
 # Use board logo and fallback to vendor
-ifneq ($(wildcard logos/$(BOARD).bmp),)
+ifneq ($(wildcard $(srctree)/$(src)/logos/$(BOARD).bmp),)
 LOGO_BMP= $(srctree)/$(src)/logos/$(BOARD).bmp
 else
-ifneq ($(wildcard logos/$(VENDOR).bmp),)
+ifneq ($(wildcard $(srctree)/$(src)/logos/$(VENDOR).bmp),)
 LOGO_BMP= $(srctree)/$(src)/logos/$(VENDOR).bmp
 endif
 endif