r600: set the number type correctly for float rts in cb setup

r600: set the number type correctly for float rts in cb setup

Float rts were always set as unorm instead of float.
Not sure of the consequences, but at least it looks like the blend clamp
would have been enabled, which is against the rules (only eg really bothered
to even attempt to specify this correctly, r600 always used clamp anyway).
Albeit r600 (not r700) setup still looks bugged to me due to never setting
BLEND_FLOAT32 which must be set according to docs...
Not sure if the hw really cares, no piglit change (on eg/juniper).

Reviewed-by: Dave Airlie <airlied@redhat.com>