freedreno/a6xx: move where we handle dirty vbo state

freedreno/a6xx: move where we handle dirty vbo state

Historically this wasn't in fdN_emit_state(), because prior to addition
of blitter in a5xx, fdN_emit_state() was also used in the clear path.
These days that is only true for a2xx (a3xx and a4xx use u_blitter).  So
the reason for it not to be in fd6_emit_state() no longer exists.

Signed-off-by: Rob Clark <robdclark@gmail.com>