drm/bridge: tc358767: Fix comment in tc_edp_mode_valid

Fix comment copy-paste error in tc_edp_mode_valid(), this function
is validating DP/eDP clock, not DPI clock frequency. Update the
comment to match. No functional change.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240531203213.277421-1-marex@denx.de