usb: typec: ucsi: displayport: NAK DP_CMD_CONFIGURE without a payload VDO

usb: typec: ucsi: displayport: NAK DP_CMD_CONFIGURE without a payload VDO

ucsi_displayport_vdm() handles a DP_CMD_CONFIGURE by copying the first
payload VDO from data[], but unlike the equivalent handler in
altmodes/displayport.c it does not check that count covers a VDO beyond
the header.  A header-only Configure VDM (count == 1) would read one u32
past the caller's array.

In the normal UCSI path the caller controls count, so this is hardening
for non-standard delivery paths.  NAK and bail when no configuration VDO
is present, matching the generic DP altmode driver's existing guard.

Assisted-by: gkh_clanker_t1000
Cc: Pooja Katiyar <pooja.katiyar@intel.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: stable <stable@kernel.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/2026051351-vividly-flattered-eb3d@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>