HSI: hsi_char: Add HSI char device kernel configuration

Add HSI character device kernel configuration

Signed-off-by: Andras Domokos <andras.domokos@nokia.com>
Signed-off-by: Carlos Chinea <carlos.chinea@nokia.com>
diff --git a/drivers/hsi/clients/Kconfig b/drivers/hsi/clients/Kconfig
new file mode 100644
index 0000000..3bacd27
--- /dev/null
+++ b/drivers/hsi/clients/Kconfig
@@ -0,0 +1,13 @@
+#
+# HSI clients configuration
+#
+
+comment "HSI clients"
+
+config HSI_CHAR
+	tristate "HSI/SSI character driver"
+	depends on HSI
+	---help---
+	  If you say Y here, you will enable the HSI/SSI character driver.
+	  This driver provides a simple character device interface for
+	  serial communication with the cellular modem over HSI/SSI bus.