art: fix -Wc99-designator

Nested designated initialization is a C99 feature.

Alternatively, we could disable this warning as other Android projects
have chosen to do.

Bug: 139945549
Test: mm
Change-Id: Ic33089cc1d88100f01c44cc9890c461ed6fd7450
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
1 file changed