drm/amd/display: Use switch table for dc_to_smu_clock_type

Using a static int array will cause errors if the given dm_pp_clk_type
is out-of-bounds. For robustness, use a switch table, with a default
case to handle all invalid values.

v2: 0 is a valid clock type for smu_clk_type. Return SMU_CLK_COUNT
    instead on invalid mapping.

Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c

@@ -151,18 +151,31 @@ static void get_default_clock_levels(
 static enum smu_clk_type dc_to_smu_clock_type(
 		enum dm_pp_clock_type dm_pp_clk_type)
 {
-#define DCCLK_MAP_SMUCLK(dcclk, smuclk) \
-	[dcclk] = smuclk
-
-	static int dc_clk_type_map[] = {
-		DCCLK_MAP_SMUCLK(DM_PP_CLOCK_TYPE_DISPLAY_CLK,	SMU_DISPCLK),
-		DCCLK_MAP_SMUCLK(DM_PP_CLOCK_TYPE_ENGINE_CLK,	SMU_GFXCLK),
-		DCCLK_MAP_SMUCLK(DM_PP_CLOCK_TYPE_MEMORY_CLK,	SMU_MCLK),
-		DCCLK_MAP_SMUCLK(DM_PP_CLOCK_TYPE_DCEFCLK,	SMU_DCEFCLK),
-		DCCLK_MAP_SMUCLK(DM_PP_CLOCK_TYPE_SOCCLK,	SMU_SOCCLK),
-	};
-
-	return dc_clk_type_map[dm_pp_clk_type];
+	enum smu_clk_type smu_clk_type = SMU_CLK_COUNT;
+
+	switch (dm_pp_clk_type) {
+	case DM_PP_CLOCK_TYPE_DISPLAY_CLK:
+		smu_clk_type = SMU_DISPCLK;
+		break;
+	case DM_PP_CLOCK_TYPE_ENGINE_CLK:
+		smu_clk_type = SMU_GFXCLK;
+		break;
+	case DM_PP_CLOCK_TYPE_MEMORY_CLK:
+		smu_clk_type = SMU_MCLK;
+		break;
+	case DM_PP_CLOCK_TYPE_DCEFCLK:
+		smu_clk_type = SMU_DCEFCLK;
+		break;
+	case DM_PP_CLOCK_TYPE_SOCCLK:
+		smu_clk_type = SMU_SOCCLK;
+		break;
+	default:
+		DRM_ERROR("DM_PPLIB: invalid clock type: %d!\n",
+			  dm_pp_clk_type);
+		break;
+	}
+
+	return smu_clk_type;
 }
 
 static enum amd_pp_clock_type dc_to_pp_clock_type(