freedreno: move shader-stage dirty bits to global dirty flag

freedreno: move shader-stage dirty bits to global dirty flag

This was always a bit overly complicated, and had some issues (like
ctx->prog.dirty not getting reset at the end of the batch).  It also
required some special hacks to avoid resetting dirty state on binning
pass.  So just move it all into ctx->dirty (leaving some free bits
for future shader stages), and make FD_DIRTY_PROG just be the union
of all FD_SHADER_DIRTY_*.

Signed-off-by: Rob Clark <robclark@freedesktop.org>