FROMLIST: usb: typec: tcpm: Clear send_discover in tcpm_check_send_discover

tcpm_check_send_discover does not clear the send_discover flag
when any of the following conditions are not met.
1. data_role is TYPEC_HOST
2. link is pd_capable

Discovery indentity would anyways not be attempted during
the current session anymore when the above conditions are not
met. Hence clear the send_discover flag here to prevent
tcpm_enable_frs_work from rescheduling indefinetly.

Bug: 174693433
Link: https://lore.kernel.org/linux-usb/20201203031908.1491542-1-badhri@google.com/T/#u


Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Change-Id: I69d3137d373e303396cf37d885a9bb797331d13d