iopoll: Add readl_poll_sleep_timeout

Add readl poll API with sleep and timeout support.

This change is referenced from Linux from below commit:
commit <5f5323a14cad19323060a8cbf9d96f2280a462dd> ("iopoll:
introduce read_poll_timeout macro")

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index 76d2f95..30cdea0 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -43,6 +43,12 @@
 	(cond) ? 0 : -ETIMEDOUT; \
 })
 
+#define readx_poll_sleep_timeout(op, addr, val, cond, sleep_us, timeout_us) \
+	read_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)
+
+#define readl_poll_sleep_timeout(addr, val, cond, sleep_us, timeout_us) \
+	readx_poll_sleep_timeout(readl, addr, val, cond, sleep_us, timeout_us)
+
 #define readx_poll_timeout(op, addr, val, cond, timeout_us) \
 	read_poll_timeout(op, addr, val, cond, false, timeout_us)