samples: dap: drop 'sample.dap.bulk.nrf'

'nrf52840dk/nrf52840' is already listed under "generic" 'sample.dap.bulk',
so keeping 'sample.dap.bulk.nrf' has no value. The only difference is
dependency on 'gpio' instead of 'arduino_gpio', but
'nrf52840dk_nrf52840.overlay' references arduino header gpios only.

Signed-off-by: Marcin Niestroj <m.niestroj@emb.dev>
1 file changed