Add CARAVEL_PATH for the testbenches

verilog/dv/la_test1/Makefile

diff --git a/verilog/dv/la_test1/Makefile b/verilog/dv/la_test1/Makefile
index 33cf8ac..39f3dce 100644
--- a/verilog/dv/la_test1/Makefile
+++ b/verilog/dv/la_test1/Makefile
@@ -59,7 +59,7 @@
 	vvp $<
 
 %.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
-	${GCC_PATH}/${GCC_PREFIX}-gcc -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
+	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O verilog $< $@