ixgbe: Fix && vs || typo

"offset" can't be both 0x0 and 0xFFFF so presumably || was intended
instead of &&.  That matches with how this check is done in other
functions.

Fixes: 73834aec ("ixgbe: extend firmware version support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>