ltp-testsuite: build kernel modules when appropriate

If we're building a kernel, we can also build LTP's test modules.

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ltp-testsuite/ltp-testsuite.mk

@@ -13,6 +13,14 @@ LTP_TESTSUITE_CONF_OPTS += \
 	--with-power-management-testsuite \
 	--with-realtime-testsuite
 
+ifeq ($(BR2_LINUX_KERNEL),y)
+LTP_TESTSUITE_DEPENDENCIES += linux
+LTP_TESTSUITE_MAKE_ENV += $(LINUX_MAKE_FLAGS)
+LTP_TESTSUITE_CONF_OPTS += --with-linux-dir=$(LINUX_DIR)
+else
+LTP_TESTSUITE_CONF_OPTS += --without-modules
+endif
+
 # Needs libcap with file attrs which needs attr, so both required
 ifeq ($(BR2_PACKAGE_LIBCAP)$(BR2_PACKAGE_ATTR),yy)
 LTP_TESTSUITE_DEPENDENCIES += libcap