manifest: Update nRF hw models to latest

Update the HW models module to:
8b6001d6bdd9e2c8bb858fdb26f696f6d5f73db5

Including the following:
8b6001d CLOCK (54): Fix XOTUNE subscription sideeffecting for nrf54L15
9af1ac8 nRF54LM20: Bugfix: Add missing UART configuration
e6af4a7 RADIO: Fix register init for some devices (at least nRF54LM20)
2fe99ab CLOCK (54): Add XO24M/PLL24M/HFCLK24M
ffd578a CLOCK (54): Fixes around XOTUNE

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>