r600g: Use hardware sqrt instruction

Piglit quick tests including sqrt pass, no other regressions,
tested on radeon 6670.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

src/gallium/drivers/r600/r600_pipe.c

 	case PIPE_SHADER_CAP_TGSI_CONT_SUPPORTED:
 		return 1;
 	case PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED:
-		return 0;
+		return 1;
 	case PIPE_SHADER_CAP_INDIRECT_INPUT_ADDR:
 	case PIPE_SHADER_CAP_INDIRECT_OUTPUT_ADDR:
 	case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:

src/gallium/drivers/r600/r600_shader.c

 	{TGSI_OPCODE_SUB,	0, ALU_OP2_ADD, tgsi_op2},
 	{TGSI_OPCODE_LRP,	0, ALU_OP0_NOP, tgsi_lrp},
 	{TGSI_OPCODE_CND,	0, ALU_OP0_NOP, tgsi_unsupported},
-	/* gap */
-	{20,			0, ALU_OP0_NOP, tgsi_unsupported},
+	{TGSI_OPCODE_SQRT,	0, ALU_OP1_SQRT_IEEE, tgsi_trans_srcx_replicate},
 	{TGSI_OPCODE_DP2A,	0, ALU_OP0_NOP, tgsi_unsupported},
 	/* gap */
 	{22,			0, ALU_OP0_NOP, tgsi_unsupported},
 	{TGSI_OPCODE_SUB,	0, ALU_OP2_ADD, tgsi_op2},
 	{TGSI_OPCODE_LRP,	0, ALU_OP0_NOP, tgsi_lrp},
 	{TGSI_OPCODE_CND,	0, ALU_OP0_NOP, tgsi_unsupported},
-	/* gap */
-	{20,			0, ALU_OP0_NOP, tgsi_unsupported},
+	{TGSI_OPCODE_SQRT,	0, ALU_OP1_SQRT_IEEE, tgsi_trans_srcx_replicate},
 	{TGSI_OPCODE_DP2A,	0, ALU_OP0_NOP, tgsi_unsupported},
 	/* gap */
 	{22,			0, ALU_OP0_NOP, tgsi_unsupported},
 	{TGSI_OPCODE_SUB,	0, ALU_OP2_ADD, tgsi_op2},
 	{TGSI_OPCODE_LRP,	0, ALU_OP0_NOP, tgsi_lrp},
 	{TGSI_OPCODE_CND,	0, ALU_OP0_NOP, tgsi_unsupported},
-	/* gap */
-	{20,			0, ALU_OP0_NOP, tgsi_unsupported},
+	{TGSI_OPCODE_SQRT,	0, ALU_OP1_SQRT_IEEE, cayman_emit_float_instr},
 	{TGSI_OPCODE_DP2A,	0, ALU_OP0_NOP, tgsi_unsupported},
 	/* gap */
 	{22,			0, ALU_OP0_NOP, tgsi_unsupported},