Fix initialization of AAC presentation struct

Otherwise the new size checks trip on this.

Bug: 27207275
Change-Id: I1f8f01097e3a88ff041b69279a6121be842f1766

static OMX_U32 setPFramesSpacing(int32_t iFramesInterval, int32_t frameRate) {
 if (iFramesInterval < 0) {
 return 0xFFFFFFFF;
 } else if (iFramesInterval == 0) {
 return 0;
 }
    OMX_U32 ret = frameRate * iFramesInterval;
 return ret;
}

static OMX_U32 setPFramesSpacing(int32_t iFramesInterval, int32_t frameRate) {
 if (iFramesInterval < 0) {
 return 0xFFFFFFFF;
 } else if (iFramesInterval == 0) {
 return 0;
 }
    OMX_U32 ret = frameRate * iFramesInterval;
 return ret;
}
