rt-tests: fix build of NPTL dependent tests

Commit 143fe5b443da4 (rt-tests: allow building subset of tests with non-NPTL
toolchains) disabled build of NPTL dependent tests unconditionally. Fix this.

[Thomas:
 - fix typo in commit title.
 - reverse condition, to use positive logic.]

Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Reported-by: "Williams Jr., Ernest L." <ernesto@slac.stanford.edu>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Alexey Brodkin <abrodkin@synpsys.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/rt-tests/rt-tests.mk

@@ -13,7 +13,9 @@ ifeq ($(BR2_PACKAGE_PYTHON),y)
 RT_TESTS_DEPENDENCIES = python
 endif
 
-ifeq ($(BR2_TOOLCHAIN_HAS_THREADS_NPTL),)
+ifeq ($(BR2_TOOLCHAIN_HAS_THREADS_NPTL),y)
+RT_TESTS_HAVE_NPTL=yes
+else
 RT_TESTS_HAVE_NPTL=no
 endif