drm/i915/dmc: Do not require specific versions

drm/i915/dmc: Do not require specific versions

Currently, i915 interacts with the Hardware and not with any DMC
ABI/API, so the API is fixed within the platform, hence no need to get
this so-tied version requirement.

v2:
  - Use link to firmware guide from kernel documentation for
    "References:" instead of mailing list thread. (Rodrigo)
  - Provide a more elaborate justification in the commit message.
    (Rodrigo)

References: https://www.kernel.org/doc/html/v6.1/driver-api/firmware/firmware-usage-guidelines.html
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221230182422.29680-2-gustavo.sousa@intel.com