iwlagn: move ISR related data to transport layer

Since the ISR is entirely in the transport layer, its data should be in the pcie
specific region.
Change sync_irq to first disable and then synchronize the IRQ.
iwl_isr and iwl_isr_ict now receive iwl_trans.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>