r600/sfn: drop range pinning for registers after RA

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37847>

src/gallium/drivers/r600/sfn/sfn_ra.cpp

@@ -393,7 +393,11 @@ register_allocation(LiveRangeMap& lrm)
       for (auto& entry : comp) {
          sfn_log << SfnLog::merge << "Set " << *entry.m_register << " to ";
          entry.m_register->set_sel(entry.m_color);
+         /* No need for any pinning past this point, keeping the flags just makes
+          * testing more difficult.
+          */
          entry.m_register->set_pin(pin_none);
+         entry.m_register->reset_flag(Register::pin_start);
          sfn_log << SfnLog::merge << *entry.m_register << "\n";
       }
    }

src/gallium/drivers/r600/sfn/tests/sfn_test_shaders.cpp

@@ -2176,7 +2176,7 @@ PROP COLOR_EXPORT_MASK:15
 PROP WRITE_ALL_COLORS:1
 INPUT LOC:0 VARYING_SLOT:32 INTERP:2
 OUTPUT LOC:0 FRAG_RESULT:2 MASK:15
-REGISTERS R0.x@fully R0.y@fully R1.xyzw
+REGISTERS R0.x R0.y
 SHADER
 ALU_GROUP_BEGIN
 ALU INTERP_ZW __.x : R0.y Param0.x {} VEC_210