drm/i915/wm: Refactor dpkgc value prepration

Refactor the value getting prepped to be written into the PKG_C_LATENCY
register by ORing the REG_FIELD_PREP values instead of having val
getting operated on twice.
We dont need the clear and val variables to be initialized.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241203084706.2126189-2-suraj.kandpal@intel.com

Author: surajk8

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

@@ -2858,7 +2858,7 @@ static void
 skl_program_dpkgc_latency(struct drm_i915_private *i915, bool enable_dpkgc)
 {
 	u32 max_latency = LNL_PKG_C_LATENCY_MASK;
-	u32 clear = 0, val = 0;
+	u32 clear, val;
 	u32 added_wake_time = 0;
 
 	if (DISPLAY_VER(i915) < 20)
@@ -2872,9 +2872,9 @@ skl_program_dpkgc_latency(struct drm_i915_private *i915, bool enable_dpkgc)
 			i915->display.sagv.block_time_us;
 	}
 
-	clear |= LNL_ADDED_WAKE_TIME_MASK | LNL_PKG_C_LATENCY_MASK;
-	val |= REG_FIELD_PREP(LNL_PKG_C_LATENCY_MASK, max_latency);
-	val |= REG_FIELD_PREP(LNL_ADDED_WAKE_TIME_MASK, added_wake_time);
+	clear = LNL_ADDED_WAKE_TIME_MASK | LNL_PKG_C_LATENCY_MASK;
+	val = REG_FIELD_PREP(LNL_PKG_C_LATENCY_MASK, max_latency) |
+		REG_FIELD_PREP(LNL_ADDED_WAKE_TIME_MASK, added_wake_time);
 
 	intel_uncore_rmw(&i915->uncore, LNL_PKG_C_LATENCY, clear, val);
 }