usb: charger: assign specific number for enum value

To work properly on every architectures and compilers, the enum value
needs to be specific numbers.

Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/1580537624-10179-1-git-send-email-peter.chen@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>