drm/amd/display: Remove redundant if conditions

[WHY]
Coverity analysis flagged the two if conditions in
dcn30_dpp.c and dcn401_dpp.c as DEADCODE since they
are never true, since the variable
'program_prealpha_dealpha' is initialized at 0 and
never chagnes.

[HOW]
Removed the variable 'program_prealpha_dealpha' and
the if conditions.
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Ivan Lipski <ivlipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c

@@ -219,7 +219,6 @@ void dpp3_cnv_setup (
 	uint32_t alpha_plane_enable = 0;
 	uint32_t dealpha_en = 0, dealpha_ablnd_en = 0;
 	uint32_t realpha_en = 0, realpha_ablnd_en = 0;
-	uint32_t program_prealpha_dealpha = 0;
 	struct out_csc_color_matrix tbl_entry;
 	int i;
 
@@ -347,10 +346,6 @@ void dpp3_cnv_setup (
 			CNVC_ALPHA_PLANE_ENABLE, alpha_plane_enable);
 	REG_UPDATE(FORMAT_CONTROL, FORMAT_CONTROL__ALPHA_EN, alpha_en);
 
-	if (program_prealpha_dealpha) {
-		dealpha_en = 1;
-		realpha_en = 1;
-	}
 	REG_SET_2(PRE_DEALPHA, 0,
 			PRE_DEALPHA_EN, dealpha_en,
 			PRE_DEALPHA_ABLND_EN, dealpha_ablnd_en);

drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp.c

@@ -68,7 +68,6 @@ void dpp401_dpp_setup(
 	uint32_t alpha_plane_enable = 0;
 	uint32_t dealpha_en = 0, dealpha_ablnd_en = 0;
 	uint32_t realpha_en = 0, realpha_ablnd_en = 0;
-	uint32_t program_prealpha_dealpha = 0;
 	struct out_csc_color_matrix tbl_entry;
 	int i;
 
@@ -192,10 +191,6 @@ void dpp401_dpp_setup(
 		CNVC_ALPHA_PLANE_ENABLE, alpha_plane_enable);
 	REG_UPDATE(FORMAT_CONTROL, FORMAT_CONTROL__ALPHA_EN, alpha_en);
 
-	if (program_prealpha_dealpha) {
-		dealpha_en = 1;
-		realpha_en = 1;
-	}
 	REG_SET_2(PRE_DEALPHA, 0,
 		PRE_DEALPHA_EN, dealpha_en,
 		PRE_DEALPHA_ABLND_EN, dealpha_ablnd_en);