libssh2: update InstallDev define

Use $(INSTALL_DATA) for headers and pkgconfig file.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

libs/libssh2/Makefile

@@ -52,9 +52,9 @@ define Build/InstallDev
 	$(INSTALL_DIR) $(1)/usr/include
 	$(INSTALL_DIR) $(1)/usr/lib
 	$(INSTALL_DIR) $(1)/usr/lib/pkgconfig
-	$(CP) $(PKG_INSTALL_DIR)/usr/include/*.h $(1)/usr/include/
+	$(INSTALL_DATA) $(PKG_INSTALL_DIR)/usr/include/*.h $(1)/usr/include/
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libssh2.so* $(1)/usr/lib/
-	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libssh2.pc $(1)/usr/lib/pkgconfig/
+	$(INSTALL_DATA) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libssh2.pc $(1)/usr/lib/pkgconfig/
 endef
 
 define Package/libssh2/install