r600g/sb: fix kcache handling on r6xx

Use the same limit for kcache constants in alu group on r6xx as on other
chips (two const pairs). Relaxing this will require additional checks to
make sure that all 4 consts in the group come from 2 kcache sets (clause
limit), probably without noticeable improvements of shader performance.

Signed-off-by: Vadim Girlin <vadimgirlin@gmail.com>

src/gallium/drivers/r600/sb/sb_sched.cpp

@@ -43,7 +43,11 @@ namespace r600_sb {
 using std::cerr;
 
 rp_kcache_tracker::rp_kcache_tracker(shader &sh) : rp(), uc(),
-	sel_count(sh.get_ctx().is_r600() ? 4 : 2) {}
+		// FIXME: for now we'll use "two const pairs" limit for r600, same as
+		// for other chips, otherwise additional check in alu_group_tracker is
+		// required to make sure that all 4 consts in the group fit into 2
+		// kcache sets
+		sel_count(2) {}
 
 bool rp_kcache_tracker::try_reserve(sel_chan r) {
 	unsigned sel = kc_sel(r);