ARM: uniphier: set DRAM_SPARSE flag for LD21 boards

Commit 04cd4e7215 ("ARM: uniphier: remove DRAM base address from
board parameters") accidentally unset the DRAM_SPARSE flag, and
changed the physical map of the DRAM channels.  Revive the original
behavior.

Fixes: 04cd4e7215 ("ARM: uniphier: remove DRAM base address from board parameters")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reported-by: Shunji Sato <sato.shunji@socionext.com>

arch/arm/mach-uniphier/boards.c

@@ -199,7 +199,7 @@ static const struct uniphier_board_data uniphier_ld21_data = {
 		.size = 0x40000000,
 		.width = 32,
 	},
-	.flags = UNIPHIER_BD_BOARD_LD21_GLOBAL,
+	.flags = UNIPHIER_BD_DRAM_SPARSE | UNIPHIER_BD_BOARD_LD21_GLOBAL,
 };
 #endif