seccomp: Whitelist syscalls for grunt gpu
seccomp: Whitelist syscalls for grunt gpu

BUG=b:127868532
TEST=`vmc start --enable-gpu termina` succeeds

Change-Id: Ibf18cce93ab98f5008bdada3387ee27eb6f79e61
Reviewed-on: https://chromium-review.googlesource.com/1534959
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Tested-by: Drew Davenport <0076a04f3f2b16eeeed106bf047eafe8e5331162@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: David Riley <a1c52a99f156ff41f0ea478f29291144551a02f6@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm