ice: fix stack leakage

ice: fix stack leakage

commit 949375de945f7042df2b6488228a1a2b36e69f35 upstream.

In the case of an invalid virtchannel request the driver
would return uninitialized data to the VF from the PF stack
which is a bug.  Fix by initializing the stack variable
earlier in the function before any return paths can be taken.

Fixes: 1071a8358a28 ("ice: Implement virtchnl commands for AVF support")
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>