pmic: axp: define ALDO_IN startup bit

Most AXP PMICs feature a "startup source" register, which keeps
information about how the PMIC started operation. Bit 0 in there means
it has been started by "plugging in the power cable".

Define a symbol in each PMIC's header file to be able to use that
register and bit later on.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/include/axp221.h b/include/axp221.h
index a02e9b4..8dfcc5b 100644
--- a/include/axp221.h
+++ b/include/axp221.h
@@ -52,7 +52,8 @@
 /* For axp_gpio.c */
 #ifdef CONFIG_AXP221_POWER
 #define AXP_POWER_STATUS		0x00
-#define AXP_POWER_STATUS_VBUS_PRESENT		(1 << 5)
+#define AXP_POWER_STATUS_ALDO_IN		BIT(0)
+#define AXP_POWER_STATUS_VBUS_PRESENT		BIT(5)
 #define AXP_VBUS_IPSOUT			0x30
 #define AXP_VBUS_IPSOUT_DRIVEBUS		(1 << 2)
 #define AXP_MISC_CTRL			0x8f