drm/i915/dsi: fix MIPI_BKLT_EN_1 native GPIO index

Due to copy-paste fail, MIPI_BKLT_EN_1 would always use PPS index 1,
never 0. Fix the sloppiest commit in recent memory.

Fixes: f087cfe6 ("drm/i915/dsi: add support for ICL+ native MIPI GPIO sequence")
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221220140105.313333-1-jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_dsi_vbt.c

@@ -430,7 +430,7 @@ static void icl_native_gpio_set_value(struct drm_i915_private *dev_priv,
 		break;
 	case MIPI_BKLT_EN_1:
 	case MIPI_BKLT_EN_2:
-		index = gpio == MIPI_AVDD_EN_1 ? 0 : 1;
+		index = gpio == MIPI_BKLT_EN_1 ? 0 : 1;
 
 		intel_de_rmw(dev_priv, PP_CONTROL(index), EDP_BLC_ENABLE,
 			     value ? EDP_BLC_ENABLE : 0);