drm/i915/bmg: Define IS_BATTLEMAGE macro

drm/i915/bmg: Define IS_BATTLEMAGE macro

Display code uses IS_BATTLEMAGE macro but the platform support doesn't
exist in i915. So fake IS_BATTLEMAGE macro defined to enable building
i915 code.  We should make sure the macro parameter is used in the
always-false expression so that we don't run into "unused variable"
warnings from i915 builds if the IS_BATTLEMAGE() check is the only place
the i915 pointer gets used in a function.

While we're at it, also update the IS_LUNARLAKE macro to include the
parameter in the false expression for consistency.

Signed-off-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240430172850.1881525-3-radhakrishna.sripada@intel.com