libaudio_system_headers: include libcutils_headers

This is required since system/audio.h (and one more) uses
utils/BitOps.h.

Test: works with BOARD_VNDK_VERSION := current
Bug: 33241851
(cherry picked from commit 013d4a633f73e24f877887060accc0cb74055c89)
Merged-In: I13ef898a702316ccbf8b41ec500b5fd60dce155b
Change-Id: I13ef898a702316ccbf8b41ec500b5fd60dce155b
1 file changed