drm/i915/icl: Define DSI timeout registers

This patch defines DSI_HTX_TO, DSI_LRX_H_TO, DSI_PWAIT_TO
and DSI_TA_TO registers for DSI transcoders '0' and '1'.
They are used for contention recovery on DPHY.

v2: Define SHIFT for bitfields.

v3 by Jani:
- Fix timeout bit definitions

Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0b943c028a05edfd61c511d712c65c7e8bf70211.1540900289.git.jani.nikula@intel.com