drm/display/dp: Add the remaining Square PHY patterns DPCD register definitions

DP2.1 Specs added new DPCDs definitions for square pattern configs[1]
These new definitions are used for UHBR Source Transmitter
Equalizations tests[2]. Add the 3 new values for square pattern.

v2: rebase

[1]: DP2.1 Specs - 2.12.3.6.5 Square Pattern
[2]: DP2.1 PHY CTS specs - 4.3 UHBR Source Transmitter Equalization

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Lee Shawn C <shawn.c.lee@intel.com>
Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231130231510.221143-1-khaled.almahallawy@intel.com