Remove psa header files in uninstall part

Uninstall psa header files which installed to DESTDIR.

Signed-off-by: Wu, Jheng-Jhong <goodwater.wu@gmail.com>
Signed-off-by: Victor Wu <victor_wu@bizlinktech.com>
diff --git a/Makefile b/Makefile
index f8d26d2..9344e71 100644
--- a/Makefile
+++ b/Makefile
@@ -45,6 +45,7 @@
 
 uninstall:
 	rm -rf $(DESTDIR)/include/mbedtls
+	rm -rf $(DESTDIR)/include/psa
 	rm -f $(DESTDIR)/lib/libmbedtls.*
 	rm -f $(DESTDIR)/lib/libmbedx509.*
 	rm -f $(DESTDIR)/lib/libmbedcrypto.*