Add initial test driver conforming to the new spec

Also adjusted the different makefiles accordingly.
Note: driver lifetime is currently statically defined in the header, but
this will be replaced in the future based on autogeneration of lifetime
values by a script (TBD)

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>

tests/Makefile

diff --git a/tests/Makefile b/tests/Makefile
index ffa4812..511db9d 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -80,7 +80,7 @@
 $(MBEDLIBS):
 	$(MAKE) -C ../library
 
-MBEDTLS_TEST_OBJS=$(patsubst %.c,%.o,$(wildcard src/*.c))
+MBEDTLS_TEST_OBJS=$(patsubst %.c,%.o,$(wildcard src/*.c src/drivers/*.c))
 
 mbedtls_test: $(MBEDTLS_TEST_OBJS)
 
@@ -89,6 +89,10 @@
 	echo "  CC    $<"
 	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) -o $@ -c $<
 
+src/drivers/%.o : src/drivers/%.c
+	echo "  CC    $<"
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) -o $@ -c $<
+
 C_FILES := $(addsuffix .c,$(APPS))
 
 # Wildcard target for test code generation:
@@ -130,12 +134,13 @@
 clean:
 ifndef WINDOWS
 	rm -rf $(BINARIES) *.c *.datax TESTS
-	rm -f src/*.o src/libmbed*
+	rm -f src/*.o src/drivers/*.o src/libmbed*
 else
 	if exist *.c del /Q /F *.c
 	if exist *.exe del /Q /F *.exe
 	if exist *.datax del /Q /F *.datax
 	if exist src/*.o del /Q /F src/*.o
+	if exist src/drivers/*.o del /Q /F src/drivers/*.o
 	if exist src/libmbed* del /Q /F src/libmed*
 ifneq ($(wildcard TESTS/.*),)
 	rmdir /Q /S TESTS