Setting a multisampling values of 0 or 1 are apparently
2 different cases, so I tried removing the even number
check to fix this. It didn't break any tests, but I'm
not sure how well this is covered by the tests.

Change-Id: I0e7de9b153288f0c07bde9a2f104ea1d2bf230ac
Reviewed-on: https://swiftshader-review.googlesource.com/3622Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>