ice: Cleanup an unnecessary variable initialization

Commit 3463688e6ced ("ice: Add more validation in ice_vc_cfg_irq_map_msg")
added an assignment of vsi making the assignment during declaration
unnecessary.

Also, cleanup the declaration and assignment of irqmap_info to not use two
lines in the variable declaration section.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>