drm/i915/reg: convert DP_TP_CTL/DP_TP_STATUS to REG_BIT() and friends

drm/i915/reg: convert DP_TP_CTL/DP_TP_STATUS to REG_BIT() and friends

Use the modern style for defining register contents. Expand the status
register contents a bit.

TODO: There are more VC payload mapping fields, spanning more registers,
and have more bits on more recent platforms.

v2:
- Fix DP_TP_STATUS_STREAMS_ENABLED_MASK mask (Imre)
- Drop status VC3 payload mapping for now

Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1ef15e6bb58ca847f89c9b39cbc9771cb57db408.1732106557.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>