usb mux: add comment describing mux_state_t
It is a combination of flags and also represents typec_mux enum.
BRANCH=none
TEST=none
#include "usb_charge.h"
#include "usb_pd.h"
-/* USB-C mux state */
+/*
+ * USB-C mux state
+ *
+ * A bitwise combination of the USB_PD_MUX_* flags.
+ * The bottom 2 bits also correspond to the typec_mux enum type.
+ */
typedef uint8_t mux_state_t;
/* Packing and Unpacking defines used with CONFIG_USB_PD_TCPM_TCPCI_MUX_ONLY */
