Decoder: Set prev slice type for I slice.

Fixed initialization of u1_pr_sl_type for I slice.

Bug: 70897454
Test: ran PoC before/after patch
Change-Id: I0c37317513b72236be98c2b25482a67bf2b56052
(cherry picked from commit aecdfd1aff2505da11ad48ad4f9f918054ce0c97)
1 file changed