iwlwifi: move the selects to the tristate drivers

This patch moves the following select's:
- RFKILL        : IWLWIFI_RFKILL -> IWLCORE
- RFKILL_INPUT  : IWLWIFI_RFKILL -> IWLCORE
- MAC80211_LEDS : IWL4965_LEDS   -> IWLCORE
- LEDS_CLASS    : IWL4965_LEDS   -> IWLCORE
- MAC80211_LEDS : IWL3945_LEDS   -> IWL3945
- LEDS_CLASS    : IWL3945_LEDS   -> IWL3945

The effects are:
- with IWLCORE=m and/or IWL3945=m RFKILL/RFKILL_INPUT/MAC80211_LEDS/LEDS_CLASS
  are no longer wrongly forced to y
- fixes a build error with IWLCORE=y, IWL4965=m
  might be a bug in kconfig causing it, but doing this change that is 
  anyway the right thing fixes it

Reported-by: Carlos R. Mafra <crmafra2@gmail.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>