clean up NEON vector cast warnings

Many can be fixed by (T) casts.

Some seem really silly, as if the Clang intrinsics for NEON strided
loads and stores actually take arguments of the wrong type.  Those
casts would make things less clear, so instead suppress the warning,
in source rather than in the build system.

Change-Id: I5a36c244f8fbd4ecb1b9ccf0d2b04069c5664c04
Reviewed-on: https://skia-review.googlesource.com/123242
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
6 files changed