xen/pvh: increase early stack size

While booting on an AMD EPYC box the stack canary would detect stack
overflows when using the current PVH early stack size (256). Switch to
using the value defined by BOOT_STACK_SIZE, which prevents the stack
overflow.

Cc: <[email protected]> # 4.11
Signed-off-by: Roger Pau Monné <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

Author: royger

arch/x86/xen/xen-pvh.S

@@ -170,7 +170,7 @@ canary:
 	.fill 48, 1, 0
 
 early_stack:
-	.fill 256, 1, 0
+	.fill BOOT_STACK_SIZE, 1, 0
 early_stack_end:
 
 	ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY,