usb: typec: wcove: fix the sink capabilities

USB Power Delivery Specification (v3.0) dictates in ch.
6.4.1 - Capabilities Message - that the vSafe5V Fixed Supply
Object shall always be the first object. tcpm.c now checks
that this rule is obeyed (commit 5007e1b5 "typec: tcpm
Validate source and sink caps"), and that makes the
typec_wcove.c fail to probe. The voltage is higher then what
is permitted for the vSafe5V parameter.

Dropping the voltage in the first Fixed Supply object of the
sink capabilities down to 5V, and maximum current down to
500mA, making the driver probe successfully again.

Also, removing the Battery and Variable Supply objects, as
there is no need for them.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>