drm/i915/xehpsdv: Correct parameters for IS_XEHPSDV_GT_STEP()

drm/i915/xehpsdv: Correct parameters for IS_XEHPSDV_GT_STEP()

During a rebase the parameters were partially renamed, but not
completely.  Since the subsequent patches that start using this macro
haven't landed on an upstream tree yet this didn't cause a build
failure.

Fixes: ac6485408029 ("drm/i915/xehpsdv: add initial XeHP SDV definitions")
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Caz Yokoyama <caz.yokoyama@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210723174239.1551352-2-matthew.d.roper@intel.com