target-xtensa: implement ATOMCTL SR

ATOMCTL SR controls s32c1i opcode behavior depending on targeted memory
type. See ISA, 4.3.12.4 for details.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/target-xtensa/helper.h b/target-xtensa/helper.h
index 1163c09..5b4cd27 100644
--- a/target-xtensa/helper.h
+++ b/target-xtensa/helper.h
@@ -23,6 +23,7 @@
 DEF_HELPER_3(timer_irq, void, env, i32, i32)
 DEF_HELPER_2(advance_ccount, void, env, i32)
 DEF_HELPER_1(check_interrupts, void, env)
+DEF_HELPER_3(check_atomctl, void, env, i32, i32)
 
 DEF_HELPER_2(wsr_rasid, void, env, i32)
 DEF_HELPER_FLAGS_3(rtlb0, TCG_CALL_NO_RWG_SE, i32, env, i32, i32)