mfd: Add twl4030-pwrbutton as a twl4030 child

Make that twl4030-pwrbutton.c driver probe with current
child creation api for twl4030.

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/twl4030-core.c

@@ -115,6 +115,12 @@
 
 #define TWL4030_NUM_SLAVES		4
 
+#if defined(CONFIG_INPUT_TWL4030_PWRBUTTON) \
+	|| defined(CONFIG_INPUT_TWL4030_PWBUTTON_MODULE)
+#define twl_has_pwrbutton()	true
+#else
+#define twl_has_pwrbutton()	false
+#endif
 
 /* Base Address defns for twl4030_map[] */
 
@@ -538,6 +544,13 @@ add_children(struct twl4030_platform_data *pdata, unsigned long features)
 			return PTR_ERR(child);
 	}
 
+	if (twl_has_pwrbutton()) {
+		child = add_child(1, "twl4030_pwrbutton",
+				NULL, 0, true, pdata->irq_base + 8 + 0, 0);
+		if (IS_ERR(child))
+			return PTR_ERR(child);
+	}
+
 	if (twl_has_regulator()) {
 		/*
 		child = add_regulator(TWL4030_REG_VPLL1, pdata->vpll1);