i2c_slave: add driver for rtc wake up [1/3]

PD#SWPL-116360

Problem:
need check rtc wake up

Solution:
add i2c slave driver

Verify:
a4 ba409

Change-Id: Ie14d8775054ede4e86c7ce674690f9336be2a0b5
Signed-off-by: junyi.zhao <junyi.zhao@amlogic.com>
diff --git a/Kconfig b/Kconfig
index 44bd39c..c016199 100644
--- a/Kconfig
+++ b/Kconfig
@@ -19,5 +19,6 @@
 rsource "rtc/Kconfig"
 rsource "hwspinlock/Kconfig"
 rsource "i2c/Kconfig"
+rsource "i2c_slave/Kconfig"
 rsource "ethernet/Kconfig"
 rsource "hdmirx/Kconfig"