iwlwifi: move queue functions to PCI-E

iwl_queue_inc_wrap/iwl_queue_dec_wrap aren't
shared functions, they are PCI-E specific,
so move them into the appropriate header.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>