usb: typec: Remove one bit support for the Thunderbolt rounded/non-rounded cable

Two bits support for the Thunderbolt rounded/non-rounded cable has been
added to the header file.
Hence, removing unused TBT_CABLE_ROUNDED definition from the header file.

Signed-off-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
--
changes in v2:
- Removed the fixes tag as there is no functional implication.
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Link: https://lore.kernel.org/r/20201113202503.6559-5-utkarsh.h.patel@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>