iwlwifi: don't include iwl-dev.h from iwl-devtrace.h

iwl-devtrace.h is used to declare and define trace points and
including iwl-dev.h from the file, which in turn includes other
generic headers, can lead to problems like generating duplicate copies
of generic trace points depending on the order of includes.  Don't
include iwl-dev.h from iwl-devtrace.h but include it from its users -
iwl-io.h and iwl-devtrace.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: Zhu Yi <yi.zhu@intel.com>
Cc: Intel Linux Wireless <ilw@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>