powerpc/sstep: Fix emulate_step test if VSX not present

emulate_step() tests are failing if VSX is not supported or disabled.

  emulate_step_test: lxvd2x         : FAIL
  emulate_step_test: stxvd2x        : FAIL

If !CPU_FTR_VSX, emulate_step() failure is expected and testcase should
PASS with a valid justification. After patch:

  emulate_step_test: lxvd2x         : PASS (!CPU_FTR_VSX)
  emulate_step_test: stxvd2x        : PASS (!CPU_FTR_VSX)
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/lib/test_emulate_step.c

@@ -387,10 +387,14 @@ static void __init test_lxvd2x_stxvd2x(void)
 	/* lxvd2x vsr39, r3, r4 */
 	stepped = emulate_step(&regs, TEST_LXVD2X(39, 3, 4));
 
-	if (stepped == 1)
+	if (stepped == 1 && cpu_has_feature(CPU_FTR_VSX)) {
 		show_result("lxvd2x", "PASS");
-	else
-		show_result("lxvd2x", "FAIL");
+	} else {
+		if (!cpu_has_feature(CPU_FTR_VSX))
+			show_result("lxvd2x", "PASS (!CPU_FTR_VSX)");
+		else
+			show_result("lxvd2x", "FAIL");
+	}
 
 
 	/*** stxvd2x ***/
@@ -404,10 +408,15 @@ static void __init test_lxvd2x_stxvd2x(void)
 	stepped = emulate_step(&regs, TEST_STXVD2X(39, 3, 4));
 
 	if (stepped == 1 && cached_b[0] == c.b[0] && cached_b[1] == c.b[1] &&
-	    cached_b[2] == c.b[2] && cached_b[3] == c.b[3])
+	    cached_b[2] == c.b[2] && cached_b[3] == c.b[3] &&
+	    cpu_has_feature(CPU_FTR_VSX)) {
 		show_result("stxvd2x", "PASS");
-	else
-		show_result("stxvd2x", "FAIL");
+	} else {
+		if (!cpu_has_feature(CPU_FTR_VSX))
+			show_result("stxvd2x", "PASS (!CPU_FTR_VSX)");
+		else
+			show_result("stxvd2x", "FAIL");
+	}
 }
 #else
 static void __init test_lxvd2x_stxvd2x(void)