Fix for segv in ixheaacd_read_bits_buf

When ixheaacd_drc_offset comes negative, we read
backward in bitbuffer. There was no bound check to
make sure it did not go beyond the start of bitbuffer.
This caused a SEGV.

As a fix, bound check has been added.

Bug:144134845
Test: poc in bug

Change-Id: I94c4362f26fdb463eb07f5006d0f36860aad8128
1 file changed