bfin: make the CPU macro of LDR target more genenric

Remove BFIN from the CPU macro in Makefile.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
diff --git a/Makefile b/Makefile
index 9c8a580..9d38ad2 100644
--- a/Makefile
+++ b/Makefile
@@ -827,7 +827,7 @@
 
 u-boot.ldr:	u-boot
 		$(CREATE_LDR_ENV)
-		$(LDR) -T $(CONFIG_BFIN_CPU) -c $@ $< $(LDR_FLAGS)
+		$(LDR) -T $(CONFIG_CPU) -c $@ $< $(LDR_FLAGS)
 		$(BOARD_SIZE_CHECK)
 
 OBJCOPYFLAGS_u-boot.ldr.hex := -I binary -O ihex