drivers: clock_control: nrf_auxpll: add lock timeout

This patch adds a timeout to the clock_control_on() implementation. The
reason for this timeout is to prevent system freezes when the PLL is
configured incorrectly, or, if BICR is wrong. The locking time of the
AUXPLL is <30us, however, when it starts it also starts other
dependencies which take much longer to become ready. The locking time
has been experimentally measured to be around 2ms, so a 10x bound has
been added.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>