superio: Add SMSC SIO1007 driver

The SMSC SIO1007 superio chipset integrates two ns16550 compatible
serial ports for legacy applications, 16 GPIO pins and some other
functionalities like power management.

This adds a simple driver to enable serial port and handle GPIO.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index e1e3c6b..f2b08ab 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -32,6 +32,7 @@
 obj-$(CONFIG_SANDBOX) += i2c_eeprom_emul.o
 endif
 obj-$(CONFIG_SMSC_LPC47M) += smsc_lpc47m.o
+obj-$(CONFIG_SMSC_SIO1007) += smsc_sio1007.o
 obj-$(CONFIG_STATUS_LED) += status_led.o
 obj-$(CONFIG_SANDBOX) += swap_case.o
 obj-$(CONFIG_SANDBOX) += syscon_sandbox.o