mei: me: fix irq number stored in hw struct

Commit 261b3e1f ("mei: me: store irq number in the hw struct.")
stores the irq number in the hw struct before MSI is enabled.  This
caused a regression for mei_me_synchronize_irq() waiting for the wrong
irq number.  On my laptop this causes a hang on shutdown.  Fix the issue
by storing the irq number after enabling MSI.

Fixes: 261b3e1f

 ("mei: me: store irq number in the hw struct.")
Signed-off-by: Benjamin Lee <ben@b1c1l1.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200417184538.349550-1-ben@b1c1l1.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>