tests/tcg/xtensa: conditionalize and fix s32c1i tests

Make s32c1i tests conditional on the presence of this option. Initialize
ATOMCTL SR when it's present to allow RCW transactions on uncached
memory.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

tests/tcg/xtensa/test_s32c1i.S

@@ -2,7 +2,13 @@
 
 test_suite s32c1i
 
+#if XCHAL_HAVE_S32C1I
+
 test s32c1i_nowrite
+#if XCHAL_HW_VERSION >= 230000
+    movi    a2, 0x29
+    wsr     a2, atomctl
+#endif
     movi    a2, 1f
     movi    a3, 1
     wsr     a3, scompare1
@@ -20,6 +26,10 @@ test s32c1i_nowrite
 test_end
 
 test s32c1i_write
+#if XCHAL_HW_VERSION >= 230000
+    movi    a2, 0x29
+    wsr     a2, atomctl
+#endif
     movi    a2, 1f
     movi    a3, 3
     wsr     a3, scompare1
@@ -36,4 +46,6 @@ test s32c1i_write
 .text
 test_end
 
+#endif
+
 test_suite_end