Makefile: specifiy an explicite object name rather than $(BOARD).o

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/board/keymile/kmp204x/Makefile b/board/keymile/kmp204x/Makefile
index 64eb37c..c318e08 100644
--- a/board/keymile/kmp204x/Makefile
+++ b/board/keymile/kmp204x/Makefile
@@ -12,5 +12,5 @@
 $(shell mkdir -p $(obj)../common)
 endif
 
-obj-y	:= $(BOARD).o ddr.o eth.o tlb.o pci.o law.o \
+obj-y	:= kmp204x.o ddr.o eth.o tlb.o pci.o law.o \
 	../common/common.o ../common/ivm.o