platform: Use one unified per-HART stack size macro for all platforms

As of today all platforms use 8KB of per-HART stack hence there is
no need for each platform to define its own macro or use the magic
number. Create one macro for all platforms. Platform still can use
its own version if needed.

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

platform/qemu/virt/platform.c

@@ -21,7 +21,6 @@
 /* clang-format off */
 
 #define VIRT_HART_COUNT			8
-#define VIRT_HART_STACK_SIZE		8192
 
 #define VIRT_TEST_ADDR			0x100000
 #define VIRT_TEST_FINISHER_FAIL		0x3333
@@ -159,6 +158,6 @@ const struct sbi_platform platform = {
 	.name			= "QEMU Virt Machine",
 	.features		= SBI_PLATFORM_DEFAULT_FEATURES,
 	.hart_count		= VIRT_HART_COUNT,
-	.hart_stack_size	= VIRT_HART_STACK_SIZE,
+	.hart_stack_size	= SBI_PLATFORM_DEFAULT_HART_STACK_SIZE,
 	.platform_ops_addr	= (unsigned long)&platform_ops
 };