Revert the Makefile to remove the dependency of generate_files

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>
diff --git a/Makefile b/Makefile
index 650a97d..885948c 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@
 programs: lib mbedtls_test
 	$(MAKE) -C programs
 
-lib: generated_files
+lib:
 	$(MAKE) -C library
 
 tests: lib mbedtls_test
diff --git a/library/Makefile b/library/Makefile
index 3018c5b..a5abf82 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -136,7 +136,6 @@
 	     psa_crypto_aead.o \
 	     psa_crypto_cipher.o \
 	     psa_crypto_client.o \
-	     psa_crypto_driver_wrappers.o \
 		 psa_crypto_driver_wrappers_no_static.o \
 	     psa_crypto_ecp.o \
 	     psa_crypto_ffdh.o \
@@ -209,6 +208,8 @@
 all: shared static
 endif
 
+psa_crypto.o:psa_crypto_driver_wrappers.c
+
 static: libmbedcrypto.a libmbedx509.a libmbedtls.a
 	cd ../tests && echo "This is a seedfile that contains 64 bytes (65 on Windows)......" > seedfile