r600/sfn: Initialize BlockScheduler member m_chip_family.

r600/sfn: Initialize BlockScheduler member m_chip_family.

Fix defect reported by Coverity Scan.

Uninitialized scalar field (UNINIT_CTOR)
uninit_member: Non-static class member m_chip_family is not initialized
in this constructor nor in any functions that it calls.

Fixes: e57643cf548 ("r600/sfn: Add handling for R600 indirect access alias handling")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23290>