Fix SIMD on x86

The flags I added in https://review.skia.org/1232976 only work for
64 bit builds, so this adds in the old ones on 32 bit builds.

Change-Id: Iecc41507566b6663aa7f54632f00cca9330ee3bf
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1235236
Reviewed-by: Thomas Smith <thomsmit@google.com>
Commit-Queue: Kaylee Lubick <kjlubick@google.com>