LL.TS Test LL/CON/SLA/BV-129-C fails (split)

[mtpr-ot]

With the introduction of commit "Bluetooth: controller: split: fix LL/CON/MAS/BV-74-C tx timing" (0ac4433), the test LL/CON/SLA/BV-129-C fails on EBQ.

To Reproduce
Run LL/CON/SLA/BV-129-C on EBQ on "split" controller, without coded PHY.

Expected behavior
Without commit 0ac4433 the test passes - with it, it fails.

Impact
Qualification on Zephyr 2.2 will fail.

Additional context
Non-Nordic HW platform and link layer used.

[aescolar]

CC @kruithofa @cvinayak