drm/amd/display: Set default block_size, even in unexpected cases

We're not expected to enter the default case, but not returning a
default value here is incorrect.
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Eric Bernstein <Eric.Bernstein@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubbub.c

@@ -337,6 +337,7 @@ static enum dcn_hubbub_page_table_block_size page_table_block_size_to_hw(unsigne
 		break;
 	default:
 		ASSERT(false);
+		block_size = page_table_block_size;
 		break;
 	}
 

drivers/gpu/drm/amd/display/dc/inc/hw/dchubbub.h

@@ -62,7 +62,7 @@ enum dcn_hubbub_page_table_depth {
 
 enum dcn_hubbub_page_table_block_size {
 	DCN_PAGE_TABLE_BLOCK_SIZE_4KB = 0,
-	DCN_PAGE_TABLE_BLOCK_SIZE_64KB = 4
+	DCN_PAGE_TABLE_BLOCK_SIZE_64KB = 4,
 };
 
 struct dcn_hubbub_phys_addr_config {