zephyr: tests: nrf: posix: portability.posix.common.tls.newlib fails on nrf9160dk_nrf9160

Describe the bug The test portability.posix.common.tls.newlib from tests/posix/common/ fails on nrf9160dk_nrf9160

To Reproduce Steps to reproduce the behavior:

1. Have nrf9160dk connected
2. call ./scripts/twister --device-testing -T tests/posix/common/ -p nrf9160dk_nrf9160 --device-serial /dev/ttyACM0 -v -v
3. See error

Expected behavior The test passes

Impact Not clear

Logs and console output The part containing FAIL status:

START - test_posix_realtime
POSIX clock set APIs
Assertion failed at WEST_TOPDIR/zephyr/tests/posix/common/src/clock.c:75: test_posix_realtime: (rts.tv_nsec not equal to mts.tv_nsec)
Nanoseconds not equal
FAIL - test_posix_realtime

Environment (please complete the following information):

• OS: Ubuntu 18.04
• Toolchain Zephyr SDK
• Commit Version used: Zephyr v2.5.0-rc1-11-gf91e9f