fix build bug, found by joerg.

It seems to be a problem to call PKG_INSTALL via $(shell ..)

mk/kernel-build.mk

@@ -53,8 +53,12 @@ compile: $(LINUX_DIR)/vmlinux
 install: compile
 ifneq ($(strip $(INSTALL_TARGETS)),)
 	$(TRACE) target/${ADK_TARGET}-modules-install
+ifeq ($(ADK_TARGET_PACKAGE_IPKG),y)
+	$(PKG_INSTALL) $(INSTALL_TARGETS) $(MAKE_TRACE)
+else
 	$(foreach pkg,$(INSTALL_TARGETS),$(shell $(PKG_INSTALL) $(pkg)))
 endif
+endif
 
 clean:
 	rm -rf $(LINUX_BUILD_DIR)