platform: ariane-fpga: Set per-HART stack size to 8KB

Recent commit

  4a603eb ("platform: kendryte/k210: Set per-HART stack size to 8KB")

forgot to update ariane-fpga codes, and the following commit

  678c3c3 ("include: sbi_scratch: Set per-HART scratch size to 4KB")

changed the per-HART scratch size to 4KB, which potentially breaks
ariane-fpga platform.

This patch set per-HART stack size of ariane-fpga to 8KB for consistency.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

platform/ariane-fpga/platform.c

@@ -201,6 +201,6 @@ const struct sbi_platform platform = {
 	.name = "ARIANE RISC-V",
 	.features = SBI_ARIANE_FEATURES,
 	.hart_count = ARIANE_HART_COUNT,
-	.hart_stack_size = 4096,
+	.hart_stack_size = 8192,
 	.platform_ops_addr = (unsigned long)&platform_ops
 };