drm/i915/xe3lpd: Power request asserting/deasserting

There is a HW issue that arises when there are race conditions
between TCSS entering/exiting TC7 or TC10 states while the
driver is asserting/deasserting TCSS power request. As a
workaround, Display driver will implement a mailbox sequence
to ensure that the TCSS is in TC0 when TCSS power request is
asserted/deasserted.

The sequence is the following

1. Read mailbox command status and wait until run/busy bit is
   clear
2. Write mailbox data value '1' for power request asserting
   and '0' for power request deasserting
3. Write mailbox command run/busy bit and command value with 0x1
4. Read mailbox command and wait until run/busy bit is clear
   before continuing power request.

v2: Rename WA function (Gustavo)
    Limit WA only for PTL platform with a TODO note (Gustavo)
    Add TCSS_DISP_MAILBOX_IN_CMD_RUN_BUSY for clarity when writing
    register data (Gustavo)
    Move register defs from i915_reg.h to intel_cx0_phy_regs.h (Gustavo)
v3: Use "struct intel_display" instead of "struct drm_i915_private" (Jani)
    Move defs above C10 definitions in the
    intel_cx0_phy_regs.h file (Gustavo)
    Move drm_WARN_ON() inside WA function (Gustavo)
    Rename workaround function as wa_14020908590() (Gustvo)
    Use boolean enable instead of if-else structure (Raag)
v4: Drop drm_WARN_ON() (Raag)
    Fix function definition to fit into a single line (Raag)
v5: Drop TCSS_DISP_MAILBOX_IN_CMD_RUN_BUSY from TCSS_DISP_MAILBOX_IN_CMD_DATA(val)
    macro (Jani)
    Rename WA function with some meaningful name and add comment
    on WA number (Jani)
    Use struct intel_display on WA calling function (Jani)

Reviewed-by: Raag Jadav <raag.jadav@intel.com> (v4)
Acked-by: Jani Nikula <jani.nikula@intel.com> (v5)
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241127073200.124907-2-mika.kahola@intel.com

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