drivers: counters: Fix TIMER0 and RTC0 with Bluetooth controller

Fix TIMER0 and RTC0 being selectable when using out-of-tree Bluetooth
controller.
Generalize the Kconfig to have the features that use the HW peripheral
select them as reserved to make the dependencies more manageable.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>