vmxnet3: fix minimum vectors alloc issue

'Commit 39f9895a ("vmxnet3: add support for 32 Tx/Rx queues")'
added support for 32Tx/Rx queues. Within that patch, value of
VMXNET3_LINUX_MIN_MSIX_VECT was updated.

However, there is a case (numvcpus = 2) which actually requires 3
intrs which matches VMXNET3_LINUX_MIN_MSIX_VECT which then is
treated as failure by stack to allocate more vectors. This patch
fixes this issue.

Fixes: 39f9895a

 ("vmxnet3: add support for 32 Tx/Rx queues")
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Guolin Yang <gyang@vmware.com>
Link: https://lore.kernel.org/r/20211207081737.14000-1-doshir@vmware.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>