can: netlink: remove useless check in can_tdc_changelink()

can: netlink: remove useless check in can_tdc_changelink()

can_tdc_changelink() return -EOPNOTSUPP under this condition:

  !tdc_const || !can_fd_tdc_is_enabled(priv)

But this function is only called if the data[IFLA_CAN_TDC] parameters
are provided. At this point, can_validate_tdc() already checked that
either of the tdc auto or tdc manual control modes were provided, that
is to say, can_fd_tdc_is_enabled(priv) must be true.

Because the right hand operand of this condition is always true,
remove it.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-8-e720d28f66fe@kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>