freedreno/a3xx: drop hand-coded blit/solid shaders

freedreno/a3xx: drop hand-coded blit/solid shaders

Instead in the common code, construct these shaders from TGSI.  For now
we let a2xx keep it's hand coded shaders, as it's compiler isn't quite
up to the job yet.  All the same it is a net drop in code size and gets
rid of special cases.

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